Even the best SSDs on the market (which you cannot assume that PC users have) does not perform nearly as well as DDR4 RAM in terms of speed. Add to that the fact that there is a maximum number of read/writes for flash memory in its lifetime, making it not suitable for RAM. There are RAM technologies that have been in development for some time that combine the speed and durability of RAM with permanent storage properties (the data stays when the computer is turned off), but don't know when that type of RAM will become available for computers in general, or if some other memory technologies will be invented that will change the game, but flash memory is not the answer to general purpose RAM imo.
True but even the fastest of RAMs at this point cannot compensate for the lack of an SSD anymore...the difference is just too enormous. For the super fast RAM to achieve its potential it needs to access the data on the hard drive very fast and if the hard drive has a slow read speed as HDDs do then it would be like having a Ferrari supercar but only being able to drive it around parking lots with a speed limit of of 15mph. Nice Ferrari and all but a bicycle will get you where you're going just as fast.
