True, but I have to say that Quake 1 on a 4K monitor with colored lighting looks SO good (except for the monster models which have super-low polygon counts). I first played it in 320x240 256 colors. It's almost a different game.
Another old-school game that plays well is Unreal. For a while Unreal Gold was a free download on Steam, so I grabbed it. I long ago lost my original (legit) copy. Aside from the low-poly models, Unreal has really held up over the years! It looks fantastic on a 4K monitor.
There's an open-source project for total conversion of the legendary Unreal Gold (1998) in Unreal Engine 4 with VR support, but it only has the first few levels...