iOS and Android are largely for consumer devices, .Net is largely used in the enterprise for B2B products that consumers never see. .Net and Java dominate the enterprise market. Apples and oranges.
Gee, when have we heard this before. Oh, yes: when the iPhone was released.
Blackberry's are going away, we have remote email via iOS, and its only a matter of time before other people get the gear sales has.
This is why these "mobility" servers like IBM WorkLight or SAP/Sybase Unwired are hot products.