Firstly FB needs to overcome the massive undertaking of incorporating their trillions of bytes of data on the blockchain. Generally, platforms that are being built on the blockchain successfully and without incident are relatively new companies with not much data. Markethive is doing this from scratch. They are the next generation social network but classed as a market network. The last 10 years is old technology and FB would be hard pressed to run at full capacity on the blockchain, plus that means they would have to surrender the data they use that makes them the oligarchs they are.