Joel's point was that they have to put at least some hurdle, otherwise, they would crush Borland and co, which would be a bad thing, since they provide devs useful tools.

I don't really know whether that's true or not, but it makes some sense.

Plus, MS has 99% control over the desktop, so it doesn't really make sense for them to give the tools away. Or else what, Linux will steal market share from them?