I popped open a pretty new CFL that failed (it was made sometime around 2016 to 2017) and the overall build quality was sad to say the least.

Just replaced an EoL GE CFL that made it about 2000 hours.  (lots of off/on) Put in a Feit Electric CFL replacement in its place.  I have a number of em. 

In my area, CFLs also are getting replaced. Maybe 8 Years ago, CFLs were in every single store, now there is only LED, except maybe a few pieces that didn't get sold. In the most Supermarkets there is only LED and Halogen now, in Hardware Stores there are maybe 1 or 2 models of Osram CFLs in different Wattages, some Kind of "Circline CFLi", and a bit more CFLs for an external magnetic ballasts, one Store is even Full of them. And of course, the Rest is all LED in all different Variations, and pretty much Halogen Lamps aswell. There is only one Store i know of that has many different CFLs, but this is a "cheap" store that has much old and NOS items on sale.

Maybe two years ago, my father bought an Osram CFL, but it already reached EOL after 6 Months. Others are from 2010 or 2015 and fail right now. But i have some CFLs from 2008 that still work until now.

I opened some up and in one lamp, the Tube works perfectly fine and the Ballast is dead, in 3 other lamps, the tube is dead but the Ballast works fine.

Around here Walmart and Fred Meyer have long since quit carrying CFLs except maybe Blacklight Blue versions.  Home Depot and Lowes still have them, but are pushing LED.  Small-town hardware stores still have them but I think they're just old-stock in those cases.