Specifically, this is important:
Duplication Is Not The Problem. Competition is healthy. If anything, the problem is, to stick with the evolution analogy, is that Microsoft because of its sheer might gives its creations quite the head start, to survive when the same product would die had it been released by a smaller company.
I wrote Rhino Mocks for myself. It seems to be useful for other people, which is a happy coincidence, but I wrote it for myself.
One thing that I think that Phil has missed is what exactly I am objecting to. Up to and until I am held accountable to Microsoft deliverables, I do not care about Microsoft's wasted time and effort. If such a thing happens, it is Microsoft's problem.
What I do care about is my wasted time & effort. I talked about it extensively in the past.