aside from developing windows and direct X, how did MS ever have the PC market?
They never made a real effort. they just developed the tools. And put some games on it.
They never tried to really cut a piece of the PC pie. It was only until games for windows live. which flopped. now they are trying again this gen with playanywhere and using microsoft store/xbox app.
valve had the right idea that actually made PC gaming what it is.