You’ve dropped your phone and the screen shattered. Now you’re facing a costly repair until you can get a new phone. Swapping out one piece of glass or a button doesn’t seem like it should be that expensive. Why does it cost so much to fix your stuff?
No, the screens are absolutely not cheap. They are usually the most expensive part of a phone. No idea where you get that “couple of dollars” from. Hell, I usually source used screens because new would simply be too expensive. Even with literal defects in OLEDs you can still get a decent price for them.