It's a major reason. Back when TVs were made of tubes, you could expect any tech-savvy guy to be able to learn how to go in there and swap the tubes out.

Nowadays? A techpriest that can take apart Apple's iPhone stacked PCB assemblies, replace large BGA components in there, and then put them back together and have it work is a rare specimen. And "rare" means "expensive".

A hour of labor of someone who does neurosurgery on electronics isn't going to be cheap.

Not that Apple has any good reasons to make it even harder on the madmen who attempt and learn such repairs.