It's just Nvidia that is monetizing vram.
No, it's not.
Ampere launched just at the moment 2GB GDDR6 chips started to be affordable, but they needed the added bandwidth bump from GDDR6X (only 1GB chips back in September).
Nvidia has been riding the same 1GB chip density for all cards until they have the top-end 3080 20GB (2GB x 10, probably a Ti model) available. After that, I would expect a refresh on the rest of the cards that need it (3070S 16GB at 16Gbps speed, to match that 6800), and later 3060 12GB.
AMD managed to get by with the same bus with as the RX 5700 XT, but had no complexity added by mixing memory types, so they just launched all 2GB chips.