He left Bitshares to build Steem and Eos. Everything he builds he tries to compound the value of what he built before. Eos benefits by having Bitshares and Steem migrate, while Bitshares and Steem benefit from an increased network size and more capabilities. Steem benefits them all because it introduces new people to crypto while advertising the power of Graphene blockchains. I wouldn't be surprised if he went back to Bitshares with lessons learned after Eos either. I wouldn't worry, the future's looking bright for Graphene coins.