How wide would that adoption be if not for bundled sales?

Competing with 'free' is only hard once the cost is broken out and made visible.

I was personally responsible for the purchase of 3 windows licenses last year, but I didn't use any of them. The Microsoft tax makes it seem as though things are better than they really are, it's only a couple of percent but it does make a difference and I think that percentage would be higher if people had to pay the full list price for their windows licenses.