As for etacarinae's claim that OpenSolaris devs simply won't work on Linux because they don't like it, I think that is naive. First of all the skill sets for kernel writing are the same. And secondly, by participating in Linux development, they'd be able to shape the technical aspects of Linux to better fit their idea of the "perfect" operating system.
And you really think that those talented people after working so many years on Solaris/OpenSolaris, writing books about it, working hard to build a community, and so on, would suddenly without a second thought feel miraculously relieved to finally work on that next best thing called Linux ? Now this is naive, you, for some reason talk of Linux as if "everyone knows it's the best thing anyway" and the devs working on OpenSolaris are working on it just because they're forced to, poor chaps.
Yes, some people left to work for RedHat, some to work for Apple, and so on but those who remain are dedicated to OpenSolaris.
P.S. I hope you will not find my reply too offensive and/or aggressive, but try to understand how it would feel if someone were to tell you that "we should just take the best bits from Linux and port them to OpenSolaris, then ditch Linux altogether as it's useless" and expect the Linux community to just nod and be happy about the move. This is essentially what your comment means to me.