Though you are buying one phone, you are choosing from a sea of phones and carriers. A lot of how the choice works out comes down to luck.
That is somewhat true, but it's also true for cars and laptops for many people. It's "whatever Best Buy has", or whichever car lot they happen to visit and what they are trying to move. An informed consumer can choose a phone carefully, weighing their choices. That does not mean, of course, that you'll get everything you want: the original point was a single feature: OS upgrades. That can be found. As to if anybody offers the exact feature set you want... well, that's not always available. But nor is it available for vehicles or laptops either.
Personally, my killer feature is a physical qwerty keyboard. My wife also really likes them (so she can ssh into her computing cluster). That limits our options greatly, the same as if we needed four wheel drive. That said, there are few things better documented these days than cars, phones and laptops, so you cn easily do the research to find what you want.
