Bricks-and-mortars can order lens blanks and edge the lenses themselves of course, if they have the edging machine. Older shops still do it. But modern stores just don't bother anymore: they send the order to whichever supplier they use - often ordering the lenses from one supplier then having them shipped to some el-cheapo country like Vietnam for edging, which is why it takes weeks to get new glasses.

Modern opticians are little more than sellers of overpriced frames, which is why I roll my own. They make money on the frames and lose money on everything else, including fitting. You know how I know that? Because most shops will actually charge you a flat fee if you bring your own frames - including if you do the fitting yourself like I do. It's properly outrageous.