A: SCTP is an interesting potential alternate transport, which offers multiple streams over a single connection. However, again, it requires changing the transport stack, which will make it very difficult to deploy across existing home routers. Also, SCTP alone isn't the silver bullet; application-layer changes still need to be made to efficiently use the channel between the server and client."
SCTP have the nice side effect of improving things like streaming, and games.
As for application-layer changes, I don't think it would be too difficult to do, kind of like ipv6 (I don't have anything to back this up, it's just a hunch).
SCTP deployment will much longer than SPDY, but SCTP seems to be the "right thing to do". Not only for the web, but for other things that use the network. Internet is not only http://.
UPDATE: I just realized that saying that the transition to SCTP will be like IPv6 isn't necessarily a good point for SCTP :-D ... I guess I'm a purist and not a pragmatist.