I don't think it's fair to call Windows on ARM an "engineer retention project". They actually released Windows RT and tried very hard to make it work. They still have it going with the Surface Pro X, and they just announced an emulation layer to get x64 applications working on ARM, which if it works well would solve RT's biggest problem, a lack of legacy applications: https://www.neowin.net/news/it039s-official-x64-emulation-is...