I know there is a lot of corporate alienation on the #fediverse, especially the concept of a large social space like #Tumblr federating.
GTalk openly federated with XMPP for a while. I know of no one who continued to use GTalk after they announced federation being sunset.
Basically I don't see everyone flocking to the corporate option just because it interoperates. I *detest* Tumblr's UX/UI, but I'd love to interact with folks there.