Sure choice of OS would be nice, but there's a huge number of man hours that go into making a nice touch UI. Something that experts don't tend to obsess over, unless paid.
The pixel's don't have a locked bootloader, and you could try one of the community builds, which I've done. But there's much less incentive lately. I used to root to tether, don't need to anymore.
Edit: I’m not sure why this question is getting downvoted.
I personally hate it, but I understand why they do it. I just wish we could get a class leading vanilla Android phone. Pixel isn’t it.
Manufactures really hate the lack of flexibility and there is a small amount of justification: new hardware often does need new controls.
And of course many people like the flexibility of Android.
It's just a different model. Single corporation stack gives you more consistency and less bloatware and OEM based stack gives you more market choice and greater accessibility.