I don't see what they'd have to gain from dropping the xbox. There will be a million streaming devices before your proposed Xbox cloud gaming system arrives, I'm pretty sure X1+PS4 will be streaming devices before the end of the gen. Steam and Nvidia aswell. Although X1 is causing them loses, a streaming device isn't the solution, nor is cutting the systems life. Instead they could start selling things for a profit.
Microsoft wouldn't be so aggressive with X1 pricing and deals if they didn't want to build an install base for future generations. Otherwise the X1 would be priced at a profitable $399, getting a 1up on sale units wouldn't matter to them.
Meanwhile PC will always be there for them to make money off. For the same reasons as ever though, PC gaming will never be as accessible a market as consoles.
