@JEMC Might be because MS and their first party studios having to essentially develop for 3-5 platforms for day 1 release (Xbox One/X / Series S/X and PC). And their API being shared across Series consoles and PC (DX12/DX12U ). And like you said they feel like they don't need third party tools on top of their current ones.
Sony strategy thus far is developing and releasing on their main platform/s (PlayStation consoles) then have another studio port them to over to PC, with enhancements. Wouldn't say no to day one PC ports though I don't think we should expect to see them.. at least any time soon anyway.
Either way enhanced ports is always welcome in my books! With DLSS being easier to implement I wouldn't be surprised to see MS first party titles getting patches with this. Or maybe even XeSS in the near future.
