Nobody innovated, nobody focused on the developer or bothered with creating a platform for developers although developers were asking for it. Sony, Nokia, Ericsson had big fan bases.
There were any number of customizations that people all over the world created for them. But those phone companies didn't care.
Each year, all these phone companies would come out with new form factors to keep their fan bases hooked. That's it. No standardization, no nothing.
They all lost. And deservedly so. And we were left with Google cannibalizing open-source to create Android. Even then, and now, companies only accepted Android because they saw the rise of iPhone. It was a threat. They had to scramble to get something together.
Everyone else just gave up. Even now, all I hear is, "It's not an easy task to create a new phone because you have to create everything from the ground up". It's this attitude which has been the death of mobile communication.
Instead of having something that everyone could use and build upon, we're left with brittle pieces of proprietary software, completely at the mercy of two behemoths who call all the shots.
The PC revolution happened but nobody learned anything from it.