I didn't say there isn't a difference from one type to another. Just trying to point out that more money doesn't necessarily get you a better pair.
You can spend your money as you like, as I said.
The facts are that prescription glasses are over priced and quality has zero to do with price. If someone thinks that off-the-rack sunglasses are worth the same as a pair of prescription glasses, I can't do much about it, clearly. Some offer opinions, others offer facts.