“If you’ve ever watched an “Air Products” (or similar specialty gas delivery vendor) truck deliver gases,”
OK, you were the one making fun of me because I’m not an engineer, but come on, now you are talking about refrigerated gas containers, completely different from high pressure tank construction.
No. Compressed hydrogen, helium, nitrogen, oxygen, and pretty much every other high pressure gas can be had in such composite cylinders as well as metal. They also use'em for scuba tanks, which contain similar pressures. Where did you come up with this idea of "refrigerated gas containers"?
I don't know the full extent to which composite has replaced metals, but I've seen plenty of such tanks in cylinder storage racks, and they weren't for refrigerated gases (though composite cylinders can also be used for those).