It's not feasible because there's no fee model for the users. It's a free service. With traditional "federated" networks, like telephones, the customers pay

It's not feasible because there's no fee model for the users. It's a free service. With traditional "federated" networks, like telephones, the customers pay for the service and you can mandate interoperability that includes allowed peerage fees to incentivize quality and compatibility of these connections. The proposed act requires one social network to carry messages for another with zero incentives between them. Even if you do get it implemented, I suspect it will never work with any reliability or will have so many limitations applied as to be essentially useless for the stated purpose.