Earlier quoted context omitted.
I worked on the retail IT side of things at Luxottica. I don't even think that you've scratched the surface of just how prevalent Luxottica is: you've touched the retail side of things, but, you also haven't touched the manufacturing side of things (Lux has patents on the hinges used in glasses), the wholesaling side of things (Lux supplies generic and branded frames to your local optician on less-than-preferred term…
Glasses aren't that expensive. I buy them from https://zennioptical.com I don't think that I'd ever pay more than $100 for a frame again. The sunglasses that we buy in a drugstore can be had for paltry sums, why not prescription eyewear?
If you don't want to purchase online Costco is decent price - $180ish for the progressives lenses I just purchased vs $400+ from LensCrafters. Downside of Costco is a limited selection of frames, but worth a look. Also heard good things about Warby Parker but have not purchased lenses from them.
Oh, Zenni's progressive lenses have a much narrower distance vision section in the lens than Costco's. So I get progressive glasses at Costco then single reading and computer glasses (for < $40 each) at Zenni.