Is Steve Jobs letting Microsoft catch up on features, or is he sandbagging?
No, he’s releasing “Snow” Leopard so he can pick up some pocket change to subsidize his “snow” addiction.
It looks like he's taking a release cycle to just concentrate on making things better and faster under the hood. It also looks like there are a lot of programming libraries coming to help developers easily take advantage of all of the power of a modern machine, like multiple cores and the GPU. If it's easy for developers, it means better, more powerful software for us.
Vista could definitely use that.
BTW, getting into OS X development I've noticed some things in applications. I got a library cataloging program for our obscene amount of books, movies, etc., and while using it I noticed all the cool things it did, and how they only had to leverage the built-in libraries to do them.