Another part of it might be it's harder to simulate wind dynamics then ocean and engine dynamics and VSTEP isn't ready to move up to that level quite yet.
I'd hardly say so. Code is code, and if you have the data and can crunch the numbers then it doesn't really matter what you're trying to simulate, programmers can make it if they have the specific data, as far as I would understand what's involved. But the main focus first were powered vessels.
Sailing vessel were said to become part of the sim one day, but you can't have it all right away, when you try to establish yourself in this genre, as a relatively small company, I'd guess. Plus I do suspect that VSTEP's background in creating simulators for educational and professional use, for schools, government branches, companies, etc, might also be a reason that sailing isn't part of the sim (yet). Not that I know much about it, but I guess most training goes on with powered vessels, since sailing vessels are not a major part of the nautical profession that much anymore.
And btw, what level would we be talking about? The only competitor isn't even really a true competitor at all... heh.
The people at VSTEP are more than capable to create such things, let me assure you. That they haven't yet has nothing to do with not being good enough.
Fred