On a server machine you can have more than 100GB/s of NVMe if you parallelize (RAID 0 and the like). But it's still gonna be noticeably slower.

1536GB of DDR4 ECC server RAM is somewhere between $4000-6000 USD used right now, by the time you put in parallel enough NVME SSD to approach good speeds, you'd be approaching that (and also likely running out of PCI-E bus lanes directly attached to the same motherboard to reasonably do so).