It is happening, but you gotta give it some time (just like all other converging markets, without immediate benefit).

Most Routers, IP Phones etc.. already have the capability, because all it really depends on is the IP stack of the OS those devices run on. (and most do support it)
If a stack and the belonging API know that, it really isn't that much of a deal to it, whether it's ip4 or ipv6.

This usually means a simple firmware update.