As for addressing 128 bits of memory: that's more than a century off even if memory continues to double every two years (which doesn't seem likely to begin with). It's actually plausible that the step to 64-bit addressing was the last one, ever.
(And while one could argue that a vector register isn't a "real" general-purpose register, the primary difference is that you can't perform fullwidth arithmetic, which is of very little use > 64 bits anyway.)
In most code settings, this pollutes the cache (you can only hold half as many pointers), and leads to slightly weaker performance.
64-bit computing is NOT an advantage in the phone world. It is a massive advantage for database applications or large web services... but certainly not for phone apps in the near future.