Xbox is a bit trickier presumably because of PC gaming and Sony/Nintendo, though considering it's M$ I say fuck it and force them to open it up anyways.
Microsoft was required to open up the algorithms and APIs required to become a Windows Server, Domain Controller, file server, print server, group policy object Server... everything.
That's how Samba on Linux became a completely compatible Windows domain controller. Microsoft was required to share all the information and APIs Samba required.
Do the same thing with Office software. Don't just claim the file formats are open, force the release of the algorithms needed to interpret the data in those files to allow opening modifying and saving changes in a completely compatible manner.
> Microsoft has given up its nine-year fight against antitrust regulators in Europe, saying yesterday that it would not challenge a court judgment from last month and would share technical information with rivals on terms the software giant had long resisted.
European regulators and some software groups in Europe hailed the deal as a breakthrough that should open the door to freer competition, especially in the market for the server software that powers corporate data centers and the Internet.
Oh, it absolutely would.
Break Microsoft into the "Office Apps" and "Office EMail" and "Public Email" pieces and prevent them from talking to one another by backdoor APIs. You will get all manner of competitors popping up once the APIs required to do what is needed are all public.
The biggest problem in competing with Microsoft is the integration. If you force Microsoft, itself, to have to use the same public integration as everybody else, screaming will ensue.