That's a pretty good idea. One of the cons of having seperate apps for everything is the seperation of communities. Having to build two seperate audiences over both Instagram and Facebook, for example, can be tiresome - especially for those having over 5-10 different social media accounts.

Although becoming a social media monopoly would have its cons, it would be nice to have one centralized app for all purposes with one big community. Besides, I don't see myself posting to anything outside of my profession or interest, so people would follow me for that reason only.