Why do you think so? Switching to GPLv3 wouldn't really do anything about the primary issue people have with OpenSolaris's licencing, ie the fact that it's incompatible with the Linux kernel's. It might be enough to cause some GPLv3 advocates to change focus, but I don't really see it causing any major shift in the market. Switching to GPLv2 would be more interesting, but even then I suspect that the most likely outcome would be rapid asset stripping of anything useful from Solaris into Linux. Much as it may irk me that Sun deliberately chose a Linux-incompatible licence for OpenSolaris, it still seems that it was the only way to maintain any sort of relevance.