I agree. People don't care about Windows, they care about apps, and Microsoft definitely has the inside track when it comes to apps that people actually use.
However, Microsoft is several years late to this particular party, and it is not entirely clear that they can deliver. A tablet with a four hour battery life is not going to be acceptable in most workplace situations where tablets would be a nice fit. Windows RT does a much better job of this, but it does so essentially by sacrificing compatibility with Windows software. Enterprises are already deploying tablets, and in many cases they are already developing the software that they need to switch to tablets completely. The fact of the matter is that large businesses have been switching away from deploying applications on Windows for almost a decade now. Even in most Windows shops new applications get delivered in a web browser these days.
My original point is that Microsoft has gotten itself into a very precarious situation. There are millions of iPad users that now use the iPad as their primary computing device. They don't really want an expensive new tablet that runs their employer's CRM software (or whatever), but that doesn't run the iPad applications that they have come to know and love. What they really want are replacements for the last few pieces of Windows software that they are forced to use on a PC.
Worse, thanks to competition from Google Microsoft can't even fall back on its usual tactic of providing something almost as good as the market leader at a deep discount. Google scooped up that position in mobile several years ago.
Microsoft is in a tough spot, and it is going to take more than a me-too tablet that just happens to run Windows software to turn that around. I don't think that a $900 tablet with a four hour battery life has a chance in the market, even if it does run Windows programs. Obviously you disagree. On the bright side we will find out who is right in a month or so.