I would much rather Google focus on Python than Dart for Android.
There are also lesser known alternatives such as Kotlin (by JetBrains), and you can use Groovy too.
There's a very nice testing framework in Groovy, by the way: https://code.google.com/p/spock/ - and you reportedly you can use it on Android too (I didn't try it myself yet): https://github.com/pieces029/android-spock
Or choosing Groovy-based Gradle as the main build system for Android?
Or not integrating Dart VM into Chrome?
Unlike Microsoft in their evil era - their policy has changed a lot since - they don't seem to be pushing forward their own standards and inventions at all costs, they seem very pragmatic about it.
If that decision was made by more than just some obscure team buried deep within Google's hierarchy, then why didn't Google start sponsoring the Groovy manager and 2 developers when their funding was axed by Pivotal 2 months ago?
I am curious though, why do you think that Python would be a better match for the platform ?