but it reminds me of Euro lights as found in South Africa and Australia

It would probably be able to pass as one if mixed in with a bunch of other fixtures. As far as making them out of fiberglass or plastic goes, there are plenty of designs like the ones that you mentioned that are made of plastic, and people that live in the places that those streetlights were installed don't mind them at all (even if some US members might think that they are even uglier than the Durastar, but I think they look cool like early American clamshell and "power pack" designs). I mean look at the BG 0 from Germany! That thing looks like (and is made of the the same materials as) a piece of children's playground equipment!!

The fiberglass construction does have it's advantage in coastal areas where the salt air corrodes metal and destroys it, sometimes cracking the slipfitter and making the light fall to the ground (like what have been happening to the LED Roadway NXTs in New Zealand), but the slipfitter and bracket are made out of metal, so it doesn't really matter does it.

grew up on the coast in Canada and know how much damage salt air causes and would expect a plastic / FRP / fibreglass lamp to outlast its aluminum counterpart
but in sunny Texas things are different and the AL one will last 50+ years "and look new"

I still think it's ugly even when compared to most LED luminaires. Elmhurst Mutual started installing than in 2001, and they really haven't aged all that well. Most started to stain from the rain we get eight months out of the year. Several had died within 15 years. No wonder why they installed Cooper OVH luminaires alongside them as well as started using LED luminaires in 2016.

I find that some of the LED luminaires look better than the Durastar, but I haven't been able to find one that looks like an HID cobrahead.
Even if they don't look as good as an HID cobrahead, I still prefer LEDs in some applications, especially if the fixture puts out a nice 2700K or 3000K color, has good light distribution, and has good glare control. For me, the ATBS with a DualOptix refractor and maybe also the Leotek ComfortView GreenCobra (even though they are uglier than the Durastar in my opinion because they look like toilet seats) are the best examples.

I understood why a lot of you hated the Durastar: Not only it is ugly, but it is also cheaply made. Looks more like a Chinese made lantern rather than an American made lantern in general quality and appearance.

Most AEL streetlights by this time were made in Mexico. You could have ordered a BAA (Buy American Act) compliant fixture that was made in the USA. The reason why this was (and still is) an option is because government agencies like DOTs are required to buy things that are made in the USA per the Buy American Act.

Still not a biggest fan of the design but it's still a interesting entry in the timeline of North American roadway luminaires as one of the few designs that used a largely composite construction for the housing. If I see a relatively cheap NOS example I might get it.