Microsoft's innovation days are over. They've come up with some really good stuff over the years, but they were always better at acquiring and absorbing, than inventing (remember EEE: "Embrace, Extend, Extinguish"?).
Windows 10 was supposed to take over and rule the world. Not so much, it turned out. Edge, being the great new browser in Win10, was supposed to take over and rule the world. Not so much.
So now, if they want Edge to survive, it has to be portable. It's a reasonable business decision to use Chrome as a base, and eat a little crow.
Windows is a declining, and eventually will be a minor, player for Microsoft's business. Nadella has been saying that for a few years now, and the reorg of the business units a year or so ago underscored it.
Windows US desktop marketshare up to 78% as chip deliveries have increased.
Even when considering all devices, mobile included, Windows controls highest percentage, 35%. (Worldwide, Win is on par w/ Android at 35%, as well, but dominates on desktop 79%)
So where’s the “decline”?
See here: http://gs.statcounter.com/os-market-share/desktop/united-states-of-america