Yes, the vast majority of people don't install a custom OS onto their computers, either. So for the average person, this doesn't matter.

> What you're arguing is that I should be fine with Apple because you can't install another OS.

That wasn't my interpretation of the OP. The fact that it's possible, with a lot of effort, to get a privacy-centric device after the fact means nothing for the general public because they are never going to take those steps. So I think it's still reasonable to define "the market" as whatever the devices ship with.

It's great that we have the ability to install privacy-focused operating systems on some Android devices (I have one), but if I were to suggest this to any of my friends, they would laugh me out of the room. There is far less resistance recommending Apple products.