Comment by Havoc

>flash memory was already nearing it's speed and latency

Kinda, but for small writes it's still nowhere near.

Samsung 990 Pro - IOPS 4KQD1 113 MBytes/Sec

P4800X optane - IOPS 4KQD1 206 MBytes/Sec

And that's a device 5 years newer and on a faster pcie generation.

It disappeared because the market that values above attribute is too small and its hard to market because at first glance they look about the same on a lot of metrics as you say