It's always a gamble and it depends on a lot of specifics. I thought XNA would've stuck around a little longer, especially given the new console that Microsoft is supposed to be releasing this year, I felt it would've been prudent for them to keep it around so that people can write the newest Xbox games right away.

In the case of Silverlight, I remember thinking to myself about how I would wait on it to see how it fared given the saturation of Flash everywhere else, and see how widespread the adoption was going to be. If I decided to dedicate myself to learning Silverlight I'd be very disappointed.

My gut feeling is that Durango will be able to play Windows Store games, possibly with a recompile to a slightly different platform target. So I expect there will still be a pathway.

There's still the expectation that people use C++/CX, which is terrible, but I think the "indie" path will be pretty well-formed.