I suspect one side aspect of the "integration" angle for Apple was that they were able to force the "recompile the world" moment on demand. How much performanc

I suspect one side aspect of the "integration" angle for Apple was that they were able to force the "recompile the world" moment on demand. How much performance do you get by taking, say, code originally written for a 10-year-old compiler whose default target was vanilla i486, and build wuuth a recently built compiler? I'd expect wins from targeting a more modern instruction set, plus 10 years of general "we've learned more about optimization". Microsoft can't do that without an architecture change, and if they do that, they're basically abandoning their primary push to consumers: your established software and workflow investments are no longer safe on Windows.