Well, high-end stuff is always on Nvidia and Apple Silicon seems to get some love because of its unified memory that makes it possible in first place plus its popularity among developers.
AMD seems to be popular among gamers on budget and the budget cards often don't have the VRAM required by default. So, AMD seems to be in this weird place where the people who can make it work don't care.
For what it's worth, at the consumer level AMD cards -- at least recently -- have tended to have more VRAM than Nvidia cards. My 3080 Ti, which I bought for $1400 (though it now goes for ~$1k), has less RAM (12GB) than a 6800 XT that you can get for $600 (16GB).
AMD seems to be popular among gamers on budget and the budget cards often don't have the VRAM required by default. So, AMD seems to be in this weird place where the people who can make it work don't care.