Release Candidate, yes, but not the betas of Vista.
They also have a lot of beta stuff out there, I think being a beta tester is free for most things but for the bigger stuff like Vista you have to be selected.
http://beta.microsoft.com/availableconnections.aspx
http://get.live.com/betas/home
How do you know? This is just something you are guessing at.
You're just showing blind faith in the project. What I believe is based on what's happened to other OSes. Just look at device driver issues in various OSes. Writing a driver for hardware that you don't own is difficult enough but a lot of companies aren't willing to release specs so the device has to be reverse engineered. And he won't be able to look at the Linux drivers because he can't put GPL'd code into his system.
Read what I wrote again. No essentially about it:
Then reword it because that's what I got out of it.
Again, I was comparing the gestation times.
Which is irrelevant. Any one thing, related or not, can affect the speed of a project. Hell if Robert gets sick SkyOS could be on hold indefinitely since he's the only developer. The only thing being a sole developer saves him from is infighting.
Any application can go poof and vanish at any time. History is littered with examples.
Not OSS applications, the source is out there so no matter what the original authors decide to do someone else can always pick up the pieces and maintain them.
Who knows? You are mixing opinion with speculation.
Of course I am since SkyOS hasn't actually done anything yet. But the fact remains that Linus had and still has thousands of people helping him as do the Gnome, KDE, Ubuntu, etc projects. Linux was developed by just one man for only a few months and a lot of the core stuff that we take for granted now (i.e. portability, SMP support, high memory, drivers, etc) were done by other people because he didn't have the inclination or the hardware. So it's a pretty safe bet that if Linux wasn't GPL'd it would have made a much smaller impact.