I believe it is far too early to be asking this question. Not only are there very few developers who have apps in the app store, but the platform was just released yesterday, so a tiny number of consumers have access to the app store.<p>I suspect we'll start seeing some numbers in about a month regarding Windows 8 installs, and then we'll start getting a very early idea of what percentage of consumers are downloading apps from the windows store.<p>I don't think it's a guarantee that windows users will download and pay for apps in the same way that in the early days of android, the store wasn't very lucrative, but I believe as android has improved and become the platform of choice for many, they are not comfortable paying for apps.
I think the better question might be who the exact audience will be for the Windows App Store? For example if it's going to be high end business users that might suggest doing certain apps. If it might be an older demographic that might also open some very specific doors as well. Another question to ask is how much will these users be willing to pay for an app?