If Facebook genuinely saw Path as a competitor they would simply buy it and kill it. I think it's more a case that Path's spamming tactics could have been seen to have Facebook's approval had they not intervened and put an end to it.
I'm not sure they could buy it. Path was offered $100 million early on from Google when they first released and were not getting traction. They rejected it.
David Morin appears to want to build a company for the long term, and so selling to Facebook (his old workplace) to kill the project seems unlikely.
>>David Morin appears to want to build a company for the long term, and so selling to Facebook (his old workplace) to kill the project seems unlikely.
What you want and dream, most of the time is different from the reality. Remember that he has investors and employees. Even if investors don't have enough voting shares they can put pressure (at least in the media) and the star employees will bolt to Google and Facebook unless they see $$ signs of a major buyout.
I predict that he will be looking for a face saving exit soon