4x48GB Corsair DDR5 sticks is about $500.*
Which is pretty cheap compared to the cost of my whole build and whatever other things I've spent on. Cheap is relative, but I'm just saying that if you're going to spend $3000+ on a build, and you love to work with massive datasets, VMs, and things, $500 for a metric fuckton of RAM so that your system is never, ever swapping, is a very worthwhile thing to spend on.
192GB worth of GPU will cost you about $40000, for reference, and will be less performant if your goal is just a vramfs for CPU tasks.
* Beware that using 4 DDR5 slots will cut your memory bandwidth in half on consumer motherboards and CPUs. But I willingly made that tradeoff. Maybe at some point I'll upgrade to a server motherboard and CPU.