Blocking the MS-ABK deal isn't about being a global superpower, but about MS and ABK doing business in UK. It's the same with EU, Netherlands, Japan and US.
Whatever services MS want from Activision they can purchase on an ongoing basis without blocking others like Sony just to block the competition.
Who wants Call of Duty to go xbox only like Halo?
Microsoft is a platform provider, the content creators that use their platform should be free to publish to any platform. Otherwise Microsoft bump the prices and say take it or leave it but you can't get it anywhere else.