I’d imagine this is something the HW has to support, and the software has to implement a solution via that HW support. I’m really excited to see SteamOS coming up as the next mobile linux platform. With the support from Valve, I’d consider a steam deck or similar over other tablet options.
This seems more like just a reality of LCD / LED display tech than anything. CRTs (remember those?) can do a lot of resolutions pretty well no problem, but new stuff not so much. I remember using a lower rez on early LCDs as a ‘free AA’ effect before AA got better/cheaper. This just seems like a response to folks getting ~4k or similar high rez displays and gfx card performance unable to keep up.
I was just playing around with gamescope that allows for this kind of scaling stuff (linux with AMD gfx). Seems kinda cool, but not exactly a killer feature type thing. It’s very similar to the reprojection algos used for VR.