the plastic only looks good when it isn’t all fogged over… Once that happens it looks like… Well, dirty foggy plastic haha. But I agree overall with you guys @“common sense answer” think you hit it over the head with your opinion on the matter 
I thought I read somewhere that plastic is used in lieu of glass for pedestrian safety in accidents, but I might be wrong.
@galant
"I thought I read somewhere that plastic is used in lieu of glass for pedestrian safety in accidents, but I might be wrong. "
That could be right. Now instead of injuring wayward pedestrians with glass headlights we run right smack into them because we can’t see them with our fogged headlights!
It’s kind of funny, but not really, the U.S. government banned covers on headlights until 1983, although European cars had them. I remember seeing plastic covers on old Jag XKEs.
Now we need the covers so pedestrians aren’t hurt.
CSA
I use Maguire’s PlastX, and follow that up with Blue Magic Headlight Lens Sealer:
I normally do it every other service (at the even 10K mark), and it takes about 10-15 per lens. Still have the original lights, and they still look good. So far, I’ve had the same set of bottles for ~12 years, and they’re both over half full. I’ve even done more than just my vehicles with them, so the stuff does last a while.
IMO the key to the polish method (whatever you use) is to keep it wet. If it dries out, it just makes more scratches.
Has anyone tried Wipe New? It does come with a sealant.
I am sure the change from glass to plastic is driven by cost savings. If there are other possible benefits the marketing folks will gladly tell us.
Don’t think so. Cost may play a (very) small part in it, but it’s doubtful. Retooling for every different style was never cheaper than using standard, off-the-shelf round or square lights. The new plastic shapes give the designers and engineers all kinds of style options, and also permit those ever-strived-for low wind resistance numbers - which add up to raising the MPGs across the board.
Changing glass to plastic also nets a weight savings. Every ounce counts in the race to lighten cars and get better fuel economy.
http://www.fixmyheadlights.com/blog/post/3548528
I guess the change was both for design and accident safety.
Good info Galant.