>The problem is that this network is so large and slow that it can't give you anywhere near the performance of a local SSD.

*As implemented in the public cloud providers.

You can absolutely get better than local disk speeds from SAN devices and we've been doing it for decades. To do it on-prem with flash devices will require NVMe over FC or Ethernet and an appropriate storage array. Modern all-flash array performance is measured in millions of IOPS.

Will there be a slight uptick in latency? Sure, but it's well worth it for the data services and capacity of an external array for nearly every workload.