Apps that are independent of the main pathways of the social experience are only going to attract a small niche audience. They need to be connect to a larger hub where users can discover new platforms and new content.
These hubs would be Facebook, Twitter, YouTube and sites like that. If you are not connected to these streams you are not getting a broad enough reach.
Additionally these smaller platforms attract all the big names and eventually they steal all the market share leaving a small percentage for everyone else to fight over.
Don’t get me wrong new apps will garner strong loyal followings but eventually they will need to connect to the hubs to attract new users.
Twitter isn’t going anywhere, and the real value in Twitter is how you sort through all the noise that is being dumped there. Once you do that you can quickly find more useful connections than on any other platform.
It’s all about discoverability and Twitter while it could be better is where the magic happens.