Like driving an airplane on the interstate
NVMe is a very high speed, very low latency protocol that is optimized for on-board short distance data transfers. Just like you can use an airplane to drive down the highway, you can use this protocol over longer distances by putting bridge circuitry at each end of the connection compensate for the different physics of communicating over longer distances. But now you've slowed it down and added costs - like clipping the wings and tail off the airplane to make it fit through overpasses. It would go really fast over some stretches of the highway but then have to slow way down (go through bridge chips) in other places.
TCP/IP is a great protocol for long distances and NVMe, QuickPath, and Hypertransport are great protocols for short distances. Fiberchannel and infiniband are great protocols for medium distances. Many attempts have been made over the years to jam sone of these protocols into different roles and they've generally wound up providing similar (or worse) performance at higher cost (like FC over IP).
Maybe this time it will be different.
Biting the hand that feeds IT
