I have been to both and have never had a bad prescription/experience.
Now, my Dad agrees with you completely. He had developed cataracts and the optometrist he was going to didn’t identify the problem, he couldn’t get a pair of glasses that worked. It wasn’t until he went to a ophthalmologist that he got a proper diagnosis.
Bingo . . . My problem exactly. For 15 years and three different optometrists I had cataracts and didn't know it. None of the eyeglass salesman said a word about it and only recommended I get new glasses twice a year instead of once a year. By the time I took my head out of my hieny and went to a real eye doctor I was legally blind.
Isn't anyone going to convince me that none of those 3 eyeglass salesmen that looked into my eyes didn't/couldn't see the problem. Only interested in selling more glasses.