In desktops maybe, which will be somewhat popular still among people who play a lot of games but not a majority (IDC has laptop sales at a 3 to 1 ratio to desktops in 2022, but that's not specific to people who play games, much less (2d) Factorio players specifically). The system I bought before my current one was in 2018 and mid-tier then was 2GB. There was no craze for (V)RAM at the time, more a question of which setting you want to play games at (and with which render distance) than whether a given laptop works for games at all
As of last month, Steam reports that >15% of their customers still have 4GB VRAM or less: https://store.steampowered.com/hwsurvey/Steam-Hardware-Softw...
I'm not familiar with Subnautica beyond the name, is that known for being particularly efficient?
edit: meant to say 4GB rather than 2GB in the Steam stats reference, fixed
4 GB is the recommended size, which manes >90% of steam-user are already in the optimal area. The lower recommendation is even 1 GB, which means >97% of steam user. Maybe if you play on a $100 mini-toaster, or some budget-laptot, it will get critical, but the vast majority of steam users are fine with playing this game.
Mid-tier laptop GPU in 2018 would have been a GeForce 1060, which came in either 3 or 6 GB variants. GeForce 1050 Ti came in a 2 GB variant, but I wouldn't classify that as mid-tier. The x050 variants (1050, 2050, etc) are budget tier.
Steam having a massive collection of users with older hardware doesn't really make 4GB of VRAM any larger. My current main machine reports less than 1GB since its an iGPU. (But I've seen it use over 8gb of system memory as VRAM)
>I'm not familiar with Subnautica, is that known for being particularly efficient?
Its a pretty well made unity engine game with a minimum requirement of Intel HD4000 integrated graphics. IDK if it would be consideredban efficient game vs other visually nice from this time frame like DOOM 2016 which runs really well on 4GB vram cards if you stick to 900p and below resoultions.