pixel art – Feasibility of videogames with maximal hardware support

So, for a while I’ve been interested in how to design videogames that have interesting/complex abstract mechanics, and that are fun, and that would work on a wide range of computer specifications (e.g. low RAM, little if any GPU support, etc.)
Over time, this interest has sort of morphed into thinking of development frameworks that are not tied to a particular hardware standard (e.g. the apple system, or a variant thereof, which seems to be essentially the norm nowadays.) Unfortunately I have very little experience in game design, but it seems like the most demanding features would be multimedia, AI in games with NPCs, and maybe the physics engine if there is one (but only if there’s a need to simulate many objects at once, at a relatively high precision.) Nai’vely, it seems that many of these tasks could be made less demanding simply by using a deliberately lower resolution (c.f. Terraria, Star Dew Valley, Hyper Light Drifter, Shovel Knight, Undertale, etc.) Although there is probably a limit at which the marginal benefit of pixellation is offset by the loss of visual range and/or variety, I wonder if it might also be possible to exceed the apparent limit by inviting players to generate their own pixel art and sprites as the game progresses (possibly with minimal preset ‘scaffolds’ that include features relevant to gameplay.) Would this approach be totally ridiculous/infeasible, has it been done, or would it be potentially worth looking into?