Lets see about Instagram which everyone is talking about , Leave Vine and Temple Run 2 aside for now ,
MS has been working with Facebook ever since WP7 and still there is no instagram.
Are facebook and MS on a dispute ?
If a company who had long relation with MS for like 2-3 years still haven't bought one of their app to WP , what makes you think that other devs are going to bring their apps to WP anytime in this year or next year ?
Honestly, if Google thinks depriving Windows Phone of its services will damage Microsoft, then Google is seriously retarded.
Windows Phone isn't a critical business venture for Microsoft, enterprise is... Google is competing viciously against Microsoft for enterprise as well as other web users, i.e. people who will ultimately settle on Google Apps or Office 365. Now, a smart Google would go ahead and FLOOD Windows Phone and Windows 8 with Google Drive, Gmail, YouTube, Maps, Voice, etc and
pull Windows users on PC and mobile
off of Microsoft's key revenue generators in Office, Skype, soon-to-be Bing, etc.
By doing that Google can claim to be truly platform agnostic, and pull one of the major reasons why Windows Phone is even valuable to enterprise in the first place, i.e. integration with Office 365 and other Microsoft services. If Windows Phone users themselves are on Google, then what's the use of going Microsoft? Right?
Right now, by ignoring Windows 8/RT/Phone, Google is letting a market form up that will NOT use its services. At some point there will be 100 million Windows Phone users (Nokia sold like 16 million in the past 3 quarters), that's a 100 million people on Office, Bing, Outlook.com, Skype and Xbox Music. This causes 2 problems. First, 100 million is a big and profitable market, and in turn every start-up out there will be sure to support such a platform alongside the incumbents. Now here's the thing, there might be a future Google or future Facebook among those start-ups, and them being on Windows Phone while today's Google/FB are not, that means those up-start competitors have 100 million customers that you do NOT have. Pure stupidity.