We keep saying this all the time as an excuse that it's the market leader the reason.
But I have this question.
Why hasn't MS taken advantage of these technologies themselves?
I think a lot is to do with the way MS demand that every piece of software delivers maximally for all their main goals: Gamepass, streaming, and "monetisation of engagement" or some shit like that.
Every game has to: sell on as many platforms as possible, drive Gamepass on as many Gamepass supporting platforms as possible, stream to devices where people haven't even invested in the hardware to begin with, and be as monetiseable as possible (meaning again, run on as many platforms as possible). Only the death of last gen consoles has allowed MS to move the baseline up, they didn't chose to do this to give Xbox killer apps.
Fully using Series features and making killer software helps the Series consoles, but that comes way down MS's list of priorities.
And going further and building games around a baseline of Velocity architecture, Mesh Shader, RT, and advanced upscaling is only going to limit opportunities to sell games to e.g. lower end PC gamers, or grow the Gamepass market, or monetise monetise monetise. So if you'd proposed doing that back in 2019 or 20 or 21 or 22 you'd have probably been given the boot. MS don't see it as being their job to move any faster than anyone else who makes games (and they're probably behind the likes of Rememdy).
Having a successful console was supposed to be MS's ace in the hole for building Gamepass, having a streaming service, and pushing a unified DX12U feature set, similar to how Xbone was supposed to allow MS to take over the TV. But all this comes at a cost to their core console market which they consistently deprioritise. The Golden Goose only has so many hit points: you keep cutting into it eventually it'll die.
MS focued so little on Series consoles that eventually customers decided to follow their lead. MS have withered their own console business, to the point where it's going to hurt Gamepass and also limit marketability of their cloud gaming offering.
All of which is building to this comment about a mid gen refresh Xbox:
The refreshed Series X that is likely coming this year should focus on cost reduction and modest clock bumps if they're cheap enough to get. If MS can implement boost clocks on the GPU in a cost effective manner they should do this too, becuase it will improve games while requiring
no work from MS on the games side, because they won't do it. It should include no new features, because MS won't use them.