I'm more then confident that if microsoft pulled out another company would enter.I know you probably think you want this but let me tell you. If the Xbox folds up and goes away Sony is gonna rampage. They'll be the Comcast of gaming and everyone will hate them because there won't be competition to keep them honest. Last time Sony dominated the marketplace the $600 PS3 happened because the attitude was fukk it we own this market we can do whatever we want now. If Microsoft wasn't there to keep them honest shyt would have been uglier that it was. Likewise Sony themselves has put research into anti-used game patents.
http://www.neogaf.com/forum/showthread.php?t=506560
Microsoft came along and soldiered on with that sort of policy and gamers rejected them and ran to Sony.
what if there was no company to run to? what if there was only one big dog and whatever they said went? that's the kinda future you're asking when you pray for Xbox's downfall. let's not pretend like Xbox Live didn't influence PSN because PSN was a response to Xbox Live. I'm sure we all remember the dark ages of PS2 online gameplay. having to buy an adapter just to go online for example while every Xbox easily went online to a unified network.
We need all these companies to be successful. praying for the downfall of one of them is praying for the ruination of console gaming. Sony, Nintendo, and Microsoft have all gotten big heads at one time or another and the market always had the option to defect to a different brand in response.
And funny enough as it sounds, nintendo is still here too. If microsoft left and nobody took their place you better believe a lot of 3rd party companies would crawl back to nintendo.