[wtallis]

No matter how many different platforms developers can target with a Win8 Metro app, the starting number of third-party apps for that platform is zero. There are no current Windows 7 desktop or phone apps or XBLA apps that will run on a Win8 phone. In some cases, porting will probably be easier than it otherwise would be, but it's still going to take some work.

Any game that already runs on smartphones will need to replace OpenGL ES with DirectX, and any app that currently runs on a Microsoft platform will need to be re-designed to work on a touchscreen, and still probably also re-write the whole GUI to use Metro.

The best that Microsoft can expect with Win8 as they are currently planning is for the first several months of app releases to be hasty ports that get their platform some credibility but don't actually make it look better than the alternatives, with good apps starting to show up by the end of the first year. But there's no way they'll close the gap quickly with anything other than badly-ported apps.

And in the meantime, barring massive bribery/subsidies from Microsoft, the only people who will be buying Windows phones are "early adopters" who just want to play with something different. That crowd isn't big enough to fund direct competition with Android and iOS.