The almost universal response from potential partners was: ‘We don’t understand the business model; we don’t know how we or Microsoft will make money on the plan; and we don’t necessarily trust Microsoft to be the single repository or host for this model,’

[…]

“We have made the point with them multiple times: If you believe consumers or businesses want to put all of their eggs in one basket, that’s just not a model that flies,” [Tony Scott, a chief technology officer at General Motors] said. “We’d love to convince the world that all they needed to buy were GM cars, but that’s just not the reality.”

— Is Microsoft getting ahead of itself?, an article on .NET