At the component level, Linux also empowers the chip vendors to build what they want on their own timescales and then address a large market. Even open Linux drivers are sometimes loaders for proprietary firmware, so they aren't really giving up the ability to ship code in a black box.
I don't see any of them willingly cooperating with a company that wants to manage and deliver the whole OS from the the kernel up. TLDR: The industry probably does not want a Microsoft for IoT.