I agree with most of your premises but not your conclusion. I would just say a couple of things:
1) Microsoft is intentionally blurring the line between tablets and PCs. Usage patterns will be different between one extreme -- something like the surface -- and the other extreme -- a tower PC / monitor combo. But between those extremes there's a lot of middle ground; convertible tablets, laptops with touch screens, all-in-one desktops with touch screens. I don't think it's so easy to say that most people will fall into a traditional desktop usage pattern because a lot of those people won't be using a traditional desktop computer.
2) When you're dealing with a user base the size of Windows, even a small percentage of users using the Windows Store still adds up to a lot of people in absolute numbers; competitive with what the other tablet platforms will have.
1) Microsoft is intentionally blurring the line between tablets and PCs. Usage patterns will be different between one extreme -- something like the surface -- and the other extreme -- a tower PC / monitor combo. But between those extremes there's a lot of middle ground; convertible tablets, laptops with touch screens, all-in-one desktops with touch screens. I don't think it's so easy to say that most people will fall into a traditional desktop usage pattern because a lot of those people won't be using a traditional desktop computer.
2) When you're dealing with a user base the size of Windows, even a small percentage of users using the Windows Store still adds up to a lot of people in absolute numbers; competitive with what the other tablet platforms will have.