let's face it, no amount of optimisation will make gta 6 fit in a disk

I have no idea why you're getting upvoted.. You keep saying optimisation, but for what?

Mind referencing where the 86mb claim comes from?

They're either likely including different scaled images, to help accommodate different video card VRAM configurations, or, full quality that gets scaled as required. My guess would be a few differently scaled images, as you wouldn't pull in 4K images for Scenary that is in the background for a game, and then rescale in realtime if you're not running with much VRAM (similar to icons, they have multiple scaled images too).

You've picked a bad example (EA), but there are plenty of remastered games that are absolutely fantastic compared to the original, like Command and conquer (obviously though, VRAM isn't an issue there). That isn't even the first NFS dud though (a lot of them were garbage after HP). In fact, Fairly sure I bought the latest one and it doesn't run correctly on my Rog Ally X (even when set to 30W).

One other consideration is that we're also playing games in 4K these days, which absolutely makes a difference to 1080p.

We all look back fondly to games from 20 years ago which blew our minds away, but, if you replay them, you'll absolutely see the difference. My mind was blown with Half-life 2 as an example, but, I started playing it again, and the quality difference is DEFINITELY obvious to modern games. Similar to when you switched from glide to OpenGL on Half-life 1, and it felt too crisp (and was better quality, but uglier)

Previously low resolution make things look better, and reduced expectations, but its blurring and such obscured bad textures. With 4K, even in movies, every pimple and bruise now shows clearly on camera, and blocky textures are obviously. CGI in movies becomes blatantly obvious too (watch the matrix 2 as an example). That's why resolution matters a lot more now.

Serious question, do you seriously think image lossy compression is difficult for game developers? lol