> As of last month, Steam reports that >15% of their customers still have 4GB VRAM or less

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.

> The system I bought before my current one was in 2018 and mid-tier then was 2GB.

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.

>As of last month, Steam reports that >10% of their customers have 2GB VRAM or less: https://store.steampowered.com/hwsurvey/Steam-Hardware-Softw...

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.

at that point can't you just use the integrated gpu which definitely has access to more ram?