> RAM is so incredibly cheap compared to 5/10/15/20 years ago

Compared to 20 years ago that's true. But most of the improvement happened in the first few years of that range. With the recent price spikes RAM actually costs more today than 10 years ago. If we ignore spikes and buy when the cycle of memory prices is low, DDR3 in 2012 was not much more than the price DDR5 was sitting at for the last two years.