Sure, but there are two types of game developers: those using high-performance Win32 native code game engines and everyone else. Everyone else is mostly using Java or Flash or something specific to iOS or Android.
So Microsoft has shut out the Win32 native code developers from the WP7 and mobile platforms by more or less requiring all apps be developed according to Metro specifications.
All the other developers will need to be given a reason to rewrite their app for managed code (i.e. C#) for Metro. The only real reason for professionals to undertake such a task is potential revenue, which isn't there until the users materialize.
Everyone else is mostly using Java or Flash or
something specific to iOS or Android.
That's not true, there's a large ecosystem of game developers writing in managed C#, in the form of the Xbox Live Indie Game market. It shouldn't be difficult to port those to Metro, assuming Microsoft doesn't shoot themselves in the foot somehow.
So Microsoft has shut out the Win32 native code developers from the WP7 and mobile platforms by more or less requiring all apps be developed according to Metro specifications.
All the other developers will need to be given a reason to rewrite their app for managed code (i.e. C#) for Metro. The only real reason for professionals to undertake such a task is potential revenue, which isn't there until the users materialize.