>>because the .NET IDE is hands down the best development environment out there.
Doesn't seem to be holding back the Android and iPhone developers. ;-)
Already there are people who made millions developing something mobile that would have been ignored on the PC. For example, check out "Angry Birds" that has sold millions of copies and/or is available for free supported by advertising. In 2 years time it would have been submerged in similar offerings but for now it has made some Finnish people very rich. It's going to happen for business too- e.g. it seems that most US physicians are making the switch to smartphones so there's a short window for smart healthcare apps before the incumbents come up with their own versions or buy you out. Seems to me the best IDE is the one that gets your app in front of as many people as quickly as possible.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1