Cache is insanely fast, orders of magnitude faster than ram, and basically instant compared to going to disk or another machine on the network. I would find it unlikely that they could overcome the added network latency introduced in such a system.
And to give the 1ns L1 access time some physicality. During 1 nanosecond light in vacuum travels 30 centimeters, or 12 inches. Signals in conductors travel slower. It is ridiculously short amount of time.
This means that there will absolutely never* be anything that can give faster access that is going to be farther than that from the CPU. Or more specifically half of that distance as the message to request what part of the cache to read must travel to the cache itself.
* Unless we find out FTL is possible. But it's a rather safe bet to assume no.
Edit: check this out for more info https://people.eecs.berkeley.edu/~rcs/research/interactive_l...