Gen5 SSDs sure may not seem worth it for many users, especially when there isn't mainstream software which would make full use of it (yet). And by the way, one little trick how to increase data bandwidth otherwise is to spread out running software on more than one drive - e.g. I have the OS on one NVMe SSD, and games on another, and that way the software isn't competing for available bandwidth or delaying each other's latency (when or if there is a peak of demand to access a drive).
I do have an air-flow PC case and a MB with M.2 Gen5 slot already though. So for me there isn't any extra cost getting a Gen5 SSD. Which isn't to say that I wouldn't go "ouch" if the asking price will be $200 for 1TB (with DRAM). But if I will eventually have a CPU for $500-$700 and a GPU for $900, then I don't see much a point in saving a few bucks on a storage drive, when a newer SSDs may offer better latency (especially at sustained loads) etc.