What? MS has 90% of the market share in desktop OS.
http://www.netmarketshare.com/operating-system-market-share.aspx?qprid=8&qpcustomd=0
Mobile and tablet OS sure. Desktop OS and Office is Microsoft's bread and butter. Add to that Microsoft making money off Android OS sales and well........... Apple and Android aren't even close to killing MS in OS market share or profit.
MS isn't going to drop Xbox. With the amount of investments MS has made in things like controller design and NFL exclusivity MS is clearly playing the long game. Short term sales doesn't seem to be the focus of what their doing nor does hoping to kill off the PS4. They want to be at the center of home entertainment, whatever that happens to mean to people. For some it will be games, others watching TV and sports. With the One MS is attempting to bridge the gap between those things and become the one system used for all of those things. It's a broader focus than the PS4. I believe even if MS was willing to give the PS4 an advantage in one area, like gaming, their hope is that the One will be better at what it was designed to do and have greater appeal to more people.
Regardless of the Xbox One being a success, MS is going to still want to be a the center of home entertainment in the future. There is just too much money to be made for a company that can pull it off and that is clearly MS's goal. if this idea fails they will keep trying with something else.