Chasing photorealism has been unsustainable since before MW2 came out. You could see where that line was headed. The answer has always been procedural artwork - not randomized, just rule-based. Even if an entire desert gets away with four textures for sand, those shouldn't be hand-drawn and manually-approved bitmaps. They should not be fixed-resolution. Let the machine generate them at whatever level of detail you need. Define what it's supposed to look like.

This is how that "Doom 3 on a floppy disk" game, .kkreiger, worked. It weighs 96 KB. It doesn't look like Descent. It has oodles of textures and smooth models. Blowing a few megabytes on that kind of content is a lot easier than cramming things down and a lot cheaper than mastering five hundred compressed six-channel bitmaps. Even if every rivet on a metal panel was drawn by hand with a circle tool, ship that tool, so that no matter how closely the player looks, those rivets stay circular.

You can draw rust and have it be less shiny because that's how rust is defined - and have that same smear of rust look a little bit different every time it appears, tiled across a whole battleship. Every bullet ding and cement crack can become utterly unremarkable by being completely unique and razor-sharp at macro-lens distances. You don't hire a thousand artists to manage one tree each, you hire a handful of maniacs who can define: wood. Sapling, tree, log, plank, chair, wood. Hand that to a dozen artists and watch them crank out a whole bespoke forest in an afternoon.