Due to rapid conversions to LED happening throughout the world and the discontinuation of HID and fluorescent lamps, fixtures, and ballasts, I believe that at some point, these venerable and reliable light sources will become extinct in the wild at some point and they will become rare collectors items. I wonder if anyone has a rough estimate of when HID and fluorescent lighting will become extinct. I personally estimate that these light sources will become extinct in the wild by 2050.

It's fairly tricky to predict technological advancement. Many of those predictions described as "silly" in their time ended up being actually quite conservative.

On the business side of things I feel there will be hardily anything else than LEDs by 2030. As regulations on mercury go more and more on the strict side it is my impression that they will very quickly put an end to the manufacturing of pretty much all discharge lamps (with the exception maybe of those "mercury-free" HPS lamps). From that point on, their disappearance is probably going to be very rapid. Ironically those stubborn mercury fixtures that just don't want to go out might outlast all the other non-semiconductor light sources, especially if they're forgotten, which does happen!

As pessimistic as it may sound, I can't help but look at things objectively... Perhaps it's because I'm no longer a "collector".

It's fairly tricky to predict technological advancement. Many of those predictions described as "silly" in their time ended up being actually quite conservative.

On the business side of things I feel there will be hardily anything else than LEDs by 2030. As regulations on mercury go more and more on the strict side it is my impression that they will very quickly put an end to the manufacturing of pretty much all discharge lamps (with the exception maybe of those "mercury-free" HPS lamps). From that point on, their disappearance is probably going to be very rapid. Ironically those stubborn mercury fixtures that just don't want to go out might outlast all the other non-semiconductor light sources, especially if they're forgotten, which does happen!

As pessimistic as it may sound, I can't help but look at things objectively... Perhaps it's because I'm no longer a "collector".

I think even mercury free high pressure sodium lamps will also go extinct by then due to the lower demand for HID lighting. I do have fears about some federal agencies forcing us to give up our collections due to mercury regulations.

IMO, I don’t think HID will go totally extinct just yet. Instead I think it will just become far and few overtime. Manufacturers are taking note of the declining demand, and thus either discontinuing products or cheapening the quality. There’s still places that use HID as they don’t have the funds to convert to LED therefore there’s still some demand, but that is subject to change. Only time will tell.

I think even mercury free high pressure sodium lamps will also go extinct by then due to the lower demand for HID lighting. I do have fears about some federal agencies forcing us to give up our collections due to mercury regulations.

I wouldn't worry about that very thing. Mercury regulations mostly impact businesses. I don't think we'll be forced to get rid of our lamps merely because they contain mercury. That kind of witch hunt would be nearly impossible to enforce. Imagine the number of CFLs laying around in people's homes!

IMO, I don’t think HID will go totally extinct just yet. Instead I think it will just become far and few overtime. Manufacturers are taking note of the declining demand, and thus either discontinuing products or cheapening the quality. There’s still places that use HID as they don’t have the funds to convert to LED therefore there’s still some demand, but that is subject to change. Only time will tell.

I feel like this is the most likely scenario. Due to the rapid adoption of LED in most new installations and the increasing number of LED conversions each year, I don't think the government, at least on the federal level is interesting in enacting new legislation banning HID to encorage the use of LED as they were for things like incandescent lamps. State and local regulations of course will vary. I suspect states like CA might eventually have some form of legislation but I can't see that happening in most states.

Now just like when incandescent lamps got banned, any relevant legislation will probably apply only to the manufacture and import, with sales of existing stock and private ownership still allowed. The former is fairly easy to enforce compared to the latter, especially ownership which will be impossible to enforce. 

Mercury free HPS lamps were banned in the EU, so they went extinct.

Can’t say on the US front, but from what I can see in my own area, probably extinct in the wild by 2025!

Totally extinct? Practically never, seeing how many units have been produced. Some are bound to be stored and then forgotten for decades. That said, I'd guess they'll be almost extinct roughly 50 years after production stops.

Now, if you're asking about lamps in service, I'd guess that by 2030, there will be almost no fluorescents or HIDs in active use.

I have a feeling fluorescents will still hold on a bit longer, I've actually still seen them in new constructions a few times. HID, unless it's something where orange HPS light is preferred, yeah I don't see that really making it to the 30s. I'm sure things like NEMAs will stick around in rural areas but other than that I don't know. Pretty depressing when you think about it. Imagine if LEDs had never taken off the way they have.

Interesting you mentioned new installs, electrical wholesale here don’t even stock fluorescent battens anymore, just the spare tubes, and spare HF ballasts, so I guess existing battens can be kept in service for a few years yet, but as for new, not seen this since 2015!

Unfortunately, like others, I see most HIDs will be gone by the 2030s. The rate of conversion just over the past year to LED has been crazy around here, even on private properties. I hope I'm wrong but I just never see them relamping HID fixtures, just replacing them with LED...so the demand is already low.

Extinct as a lighting workhorse? Probably very soon. General public just prefers LED, so the HID installation base is shrinking. So are the sales of the bulbs. And I think it is really a question of barely few years till the sales volume will be so low no maker will remain willing to maintain the production. At that moment only the existing stock gets consumed and then the HID will be gone.
Even the HID's not making it till 2030 would not surprise me at all, I think we are already at the stage of makers pulling out "plugs" to all the production lines. I may understand that business decision, but very sad is they even do not bother to announce the "last buy chance" upfront, instead of just informing "the line has been shut down"...

Here the LED conversion is accelerating as well. There are still villages around were they have not a single LED street light installed but there are also a lot of villages which are no completely LED. What I can say for your city is that we are scheduling all the lantern replacements till 2035. By then theoretically all HID lanterns will be replaced to LED so we still hope to get some HPS and CMH lamps for a while. The last HID lanterns to be replaced are those with CosmoWhite lamps as there are still a lot of them which we did install till 2015.   

Just to make things extra clear, by "extinct", I heard an implied meaning of "no longer in service in private/public installations". Of course they'll probably never be entirely wiped off the surface of the earth!

It's actually surprising how common are many items of older lighting technologies, but virtually all of them have been collecting dust for decades. I don't see how things will be different anytime soon. But if we're talking about rows of your favourite light fixture in use somewhere, unfortunately that's a matter of time, enjoy it while it lasts!

In this province municipalities are converting their streetlighting to LED, especially the mid-sized ones (10 to 50k people). Smaller communities may need financial support to afford an initial purchase in the 5 or even 6-digit range. Larger cities also face a significant investment. But one place where I'm curious to know when it'll start is the Quebec's transport ministry, which maintains an ENORMOUS number of streetlights. I've seen a few units spot-replaced by LEDs here and there, but I'm not aware of any plans for a province wide conversion program yet.