Honestly, I don't believe the USA will. The Episcopal church is shrinking at a rapid rate. All these politicians you've mentioned have one thing in common - they're all kind of old. And none of them are presidential material. Membership in the church has taken a nose dive and it continues to drop rapidly.
Episcopals will continue to be overrepresented in politics, but as their membership continues to drop, there's only so much over-representation can do for you.
In many ways, there is no longer an Episcopal Church. There are two wings barely within the Anglican Communion. The Diocese of Pittsburgh, to which I have numerous ties, basically left the church. It is stunning to think that the church where my parents met, where my father served as an alter boy, where my uncle sang in the choir, is no longer technically an Episcopal Church.