I get high quality glasses with contemporary styled frames at WalMart for next to nothing. Not only that but the WalMart optometrist is more competent and does a better job getting my prescription right than the private optometrist I used to see.
It's not as if WalMart is some exclusive club only available to the elite.
Anyone who wishes to do so may shop there and purchase their glasses.
They also have a very nice warranty. One pair got run over by a lawnmower, which was entirely my fault. Free replacement.
It is a choice to pay $400 or more for the same glasses you can get for $60. And as long as people are willing to pay $400, why not charge them that. Good for the price gougers. They only exist because people prefer to go to price gougers, since there is definitely not a quality improvement. Customers are simply paying more because that's what they want to do.