For example: the Moto-Q ran Windows, shoe-horned in some AT&T UX junk, and a huge nubin that stuck out in the middle. It pioneered the ever present "pocket dial." Was thinking of developing for it, but after a few dozen pocket dials, I wanted to go full Frisbee mode.
Apple cut through the 3-body problem. They controlled the UX. Such as integrated voice-mail. The carrier didn't mess with the UX. After a few months, Apple provided a decent development environment -- maybe as a response to all the jailbreak apps that we were making.
Around that time I was in a focus group. What struck me was a horror story from a Symbian developer. Their toolchain broke after an incremental update. Lost a week dealing with it. That kind-of put me off of Symbian.
Maybe the real choice for Nokia was: either the burning platform or the sharks.