I'm sure you're right about the motivations of many of the people within Google being essentially, 'to build a better platform'.

I don't believe the idea that this was an entirely altruistic goal.

I don't think what you are saying contradicts the overall idea that the underlying reason for Google to invest in Android was to protect it's access to data about users against other corporations.

I.e. Many people at Google were motivated to create a good platform. But the reason for creating a platform at all was fundamentally to make sure that it was Google's good platform. The fact that Google requires access data about customer behavior for it's business model can't just be washed away by pointing at the motivations of the people tasked with making Android successful - a lower level goal.