I do not know anyone offhand with a 200+GB RAM home computer. The GPU is not all that is needed; you need to keep the parameters and other stuff in memory too.
256gb of ddr4 rdimms only costs about $400 right now. $200 for ddr3. Not uncommon in homelabs.
I don't think 200gb ram is actually required, that's just what that cloud vm was spec'd with. Though the 175b model should see benefit with ram even beyond 200gb.