IOPS helps, but for the average user, hundreds of thousands is already functionally infinite. What matters at this point is latency. Where you really feel that is Queue Depth 1. Where you read a file that points you to other files, that point you to other files, etc. That is the exact case where the computer is still making you wait.
This happens when you start your operating system, it starts services, you launch apps, etc. Driving that latency down is the biggest improvement you'll ever see past where we are today in terms of IOPS and throughput.
This is where the latest Optane actually shines. Optane doesn't win on IOPS or throughput, but where it shines is its crazy latency (delivered at relatively low power levels). Where latencies are 10% of that of even the highest end PCIe 4.0 NVMe SSDs. Do something like launch 20 applications at once, and it'll be done in a fraction of a time compared to even something like a Samsung 980 Pro because of latency being more around 10 μs instead of 100 μs.
PCIe 5.0 SSDs will cut latencies down to where Optane is today, but driving latency under 1 μs is where we'll get into a new level of crazy.