Enterprise SSDs are delivering around 500+ MB/s, and NVMe SSDs are 10x faster, and 3D XPoint are 1000x faster.

Originally SANs were designed with hard disk drives in mind, which meant that the bottleneck was the spinning disks. With SSDs becoming exponentially faster, where is the bottleneck being shifted to? The controllers CPU?

Also is the diagram below accurate? What amount of latency is introduced in each layer of this stack?