ED runs smoothly on a PC with medium specs. You don't have to play at higher graphics settings so the lower settings shouldn't decrease FPS.
ED's graphics are clearly dated. It looks like a last-gen game that was released 3-4 years ago. That's generous because ED is 10 years old. I think this is primarily due to a lack of good anti-aliasing, ray / path tracing and the low polygon count of assets. The Odyssey assets are more detailed. Such as curves should be smooth, but are angular up close. The absence of path tracing makes the light, shadows, reflections and refractions unrealistic.
I don't disagree with you in that ED looks dated. For a recent enough engine (introduced 2021 but probably worked on for a few more years) even more so. It runs smooth (mostly) in space and stations, but near planets and on-foot it's extremely inconsistent - but I do run it at near max settings because dropping them makes the game look pretty horrible very quickly. And a lot of that inconsistency gets covered up by me using a G-sync 144hz monitor, but overall that inconsistency, combined with network related mini-freezes makes 4.0 feel extremely janky - like an early access game. I'm also not a big fan of the on-foot art style. It sometimes gives me mobile phone gaming vibes, and the updated (and also inconsistent) UI adds to that.
3.8 on the other hand is very snappy, almost no jank at all especially during transitions and planet-side, lighting is consistent (if not perfect) and it feels very smooth in all game scenarios on my 5yo PC (not so much on my prior one in fairness). The downside is the planet tech, even though I actually think airless planets in 3.8 have more 'flair' or atmosphere due to the lighting and the mist it generates for some planets, and draw distance/texture pop-in issues are less pronounced when flying with a fast ship.
3.8 visuals also have aged, no doubt, but at least they look very
clean, and while the AA isn't perfect I don't get distracted by it, unlike in 4.0. It's quite astounding to go back to it after playing on 4.0 for a while tbh.
And I think a lot of the performance gains in 4.0 have been achieved by drastically decreasing draw distance and LoD. If they'd fiddle with that again I'm sure performance would most likely tank as I have a hunch they didn't always sort out the underlying issues, and took the easier option instead. Adding more power intensive new gfx features will only make this worse imo.
Meanwhile, the devs of e.g. Eve Online and No Man's Sky keep upgrading the graphics including the ship models. The 2024 ED ships look pretty good, but the older ones need an upgrade.
I'm playing X4 a lot (1,200+ hrs now) and they're again updating their engine (DLSS and FSR) after having updated it 1/2 years ago, where they managed to not only make it look prettier but also improve performance,
and load times. And they churn out updates left right and centre - be that remodeling some of the older ships, or even
updating the actual flight model. All for free which is nice. I don't want to sound like a broken record bringing this game up all the time, but credit where credit's due. Especially for those people who only play Elite and don't know what's going on elsewhere in the industry.
But yes, NMS also looks and runs miles better than a few years ago, I actually refunded it in the early days because of performance and visual issues.
And then there's games like Cyberpunk, which came out in 2020 and looked stunning even back then (bugs and glitches notwithstanding), a year prior to Odyssey/4.0. DLSS is doing a lot of heavy lifting, and my card is too weak for ray-tracing enabled (it does look nice but the performance hit is not worth it). I run it at a stable 48fps (144hz screen so it's as smooth as 60) and it's absolutely beautiful to look at, even with standard lighting and shadows. Similar with MSFS2020 (which runs native at 1440p). Different genres, sure, but those games show what can be achieved without having to spend money on leading edge hardware, and that were released around the same time as Odyssey - which just looks weak in comparison especially in light of what hardware it requires to run smoothly (enough).
Edited for grammar and adding some additional points