This is a function of Intel's still poor architectural performance per mm² not anything inherent to the drastic impossibility of offering a half decent RAM pool for consumers in a given price tier.Intel had to inflate their BMG-G21 die to ~AD104 level to fit the 192 bit bus.
Nvidia isn't actually skimping on RAM, they are simply selling you lower end parts with higher end names and prices. That's it. We dont need to pretend it's anything else.
It's greed.