How would Microsoft destroy win32 platform?

This whole controversy seems like a big what if. Microsoft already responded to saying they weren’t doing this. Gabe Newell started a similar argument when Windows 8 came out and we all know how that worked out. Can they do this? Sure. But will they? According to them, they won’t. Microsoft wants to expand their user base, they wouldn’t be doing that if they were to screw over a majority of their existing customers.