Console have 16gb or RAM that is shared between CPU and GPU and its using 13,5gb for games (10 for GPU and 3,5 as System memory)for games. So 10gb is going to be enough for all next gen games.
Consoles don't target Ultra Settings, that's the point.
Do you find it regular that the next model up the line up has 24GB? More than twice as much.
There are games today that will use more than 8GB. Doom Eternal is a good example, and there are worse offenders, right now, not in 2 years from now.
10gb won't be even be enough for the end of 2021.