I cannot give you any convincing example of that.
My point was not about harvesting the results but the energy! The result does not matter in the end. Windows Forms, Silverlight, anything, just provide an alternative and lure developers. It's a form of a divide and conquer tactics. If (big-open-source-project-here) gets attention from some people with a will to contribute, then give them something else to contribute to - a new big and prospective development platform for example - .NET. What is wrong with Java? Or plain C for that matter? Which is more important - the result or what tools were used?
Having a ready open source product and providing it in new packaging (for free) is absolutely OK for me. That was the initial intention that went into it anyway - to be used somehow. And google actively invests development efforts and contributes back to the projects they use. WebKit is growing because of google and apple, not dying!
And the comparison of companies was not about size, but about practices. Being close to your users on one hand and being a big, greedy, anonymizing everything around you behemoth.