How can glasses from Internet vendors be so cheap? How about quality?

Sure… after I recover from the ensuing car crash…

If my frames break while I am driving (as an example) I won’t be able to see further than the steering wheel. This makes coming to a stop without ensuing mayhem… challenging.

I’ve never broken any of my lenses, I have broken frames. Sturdy frames are a requirement for me, your mileage may vary.

If having a variety of frames is important to you have at it on Zenni or WarbyParker or wherever. For me, swapping out frames on my “eyewear” is not the priority - getting something that can fit with my prescription, is durable, and have a fine-tuned fit to me is my priority. I’ve actually had the same style of frame for the past 10 years or so, so clearly having different shapes/colors/etc. is not a thing for me.