Android is in exponential growth as shown in the next graph,
But remember, it’s a platform only 2.5 years old, so let first PC-history be our guide:
And the final result of that era of computing, summarized in the following graph showing total market share as percentages,
And even though prediction markets are being used within corporations to peer into the future of these questions, they are of no use for making public predictions about future platform market shares due to their very low volumes and the enormous cash on the balance sheets of the tech companies involved, that is, the results would be too easy to subvert to ever be trusted.
So beware! Keep your development options open!