Yeah it's always annoying, although you pay the price for that VRAM. But 10GB should be enough to play in 4K with all details, having a bit extra would be nice (12GB or 16GB), but I don't really see the point of 24GB, for gaming at least.
The 3090 is targeted at AI ie, deep learning..., if for gaming 24gb makes no sense, not bad to have but no point in having for games that amount right now, 16gb should be the normal for 2020, 2016 was 8gb, only 16gb makes sense for a flagship like rtx 3080 in this time and age. It seems micron is having a hard time to produce enough gddrx6 for it, they dont want to sacrifice the ones on 3090 and want the 3080 to take the hit, I guess the 3090 has a higher margin of profit, so the good gddrx6 memory modules will all go to 3090 and the leftover to 3080. I guess nvidia will launch a super later on with 16gb.