Google are bad at building developer communities (or at the very least they don't care about it much). They build things for themselves and their way is the Ivory Tower way of running a community. The overlords decide and their word is set in stone, the plebs should just accept the fact that their concerns and use cases are just too trivial and they should listen to the smart people at google and do it their way, which is the only way.
This isn't the first time google open sources internal tools, trying to build a community but really ignoring them completely. GWT, Closure compiler and of course Angular comes to mind.
Angular built a great momentum and community, and the angular team at google basically ignored most ongoing concerns to work on their next big project that'll fix everything (first it was Object.observe, then dart then angular 2).
Contrast google's handling of Angular to Facebook's handling of React (and react-native) - The routinely incorporate community influencers into the core team, they include other major corporations in their decisions and community, actively engage in developer relations to get feedback, explain controversial choices and build a community.
Sun's model with Java is even more different - incorporating major stakehodlers in the language into the actual decision process via the JCP.
Of course Google isn't the only ones who are bad at building developer communities around their open source. Apple and Amazon barely even try.
If google is Ivory tower, Microsoft is the Herbalife way of building a developer community - actively supporting influencers, providing official seals of approval and using a top down hierarchy of advocates. They do listen to community input a lot more, but Microsoft is still the overlords of all their projects.