Can Windows Phone 7 help Microsoft ?

Can Windows Phone 7 series really pull Microsoft back into the game after a 2 year long steady decline.

The fact that one needs to consider is that there are only so many smart phone users out there, and the market share that Microsoft lost has already been picked up by RIM and Apple, so is there any space for Microsoft to move back into.

Is WP7 going to be a strong enough contender to motivate people to switch back from Apple, RIM, etc.

Another consideration would be the multiple paid apps that one might have bought for their current device, moving to a different platform would mean that these apps would be wasted. To add to that by the time WP7 comes out the iPad would have been in the market for a solid 3 months at least, by which time more people could adopt the iPhone because of inter portability of apps between the iPhone and the iPad. One of the reasons that I will probably buy an iPad is because I already own a lot of paid apps for the platform.

Media is already suggesting that with the news of no reverse compatibility with current gen WM 6.5 devices for WP7 there could be a further accelerated decline in smartphone MS marketshare.

So no matter how good WP7 is, its going to be an uphill battle. So did Microsoft come too late to the party, with not enough to do battle against the mighty Apple, RIM, Android, etc.