Considering that the web platform is also an offline application platform an major operation system vendor (MS, Apple, Google) cannot afford to stay out of that game.

That ignores that - for at least the last 16 years - Windows has exposed a WebBrowser control which developers can use in their applications. MS could potentially remove the IE icon and some of the UI, but removing the core browser component and rendering code would break third-party applications, and Microsoft has historically been extremely unwilling to do that.

That sounds totally radical when you first hear it but it actually makes total sense to me. I guess they're just trying to avoid technological domination by Google. Right now they still have a player in the game thanks to Edge. If they were to lose that player Google would be able to make technological choices that might be harmful to Microsoft?