Yeah, that was maybe 45 years ago when acrylic tanks were first being made or if cheap acrylic is used. Any of the name brand tanks or reputable custom fabrication companies will be using good acrylic. I have two that are over 30 years old, no yellowing, but beat to heck...LOL
benefits of acrylic are;
close too 100% clarity/no color (colorless glass costs a premium)
better insulation/less heat transfer
virtually leak proof
can be easily DIY drilled and plumbed
scratches easily BUT they can be buffed and polished out
depending on the construction and other factors, sometimes the top bracing can warp from the lights.
benefits of glass;
you can usually work inside a glass tank easier than an acrylic
the drawbacks of glass are pretty much the opposite of the benefits of acrylic.
glass can be scratched as well, it isn't as easy, but you can't buff out the scratches in glass very easily either, so.....
acrylic always trumps glass