http://hothardware.com/cs/forums/t/52864.aspx
“the WP7 app store is growing at a faster rate than Android’s app store when it launched, so there’s definitely positive news to go around. But it will still be a few quarters in our mind before we can tell if WP7 really has traction in a world already dominated by iOS, Android and BlackBerry.”
I think it really comes down to WP7 in competition with Android and Blackberry.
Apple's part in the competition boils down to people's choices of hardware.