To maybe fix AA they would have to implement DLAA, which is a subset of DLSS as in it provides AI reconstruction but no upscaling, which usually is not available in any DLSS2 implementation.
AMD as far as i know, does not have an official equivalent for DLAA, but i've read about a modded FRS2 implementation that apparently is having a similar effect to DLAA
DLAA is DLSS with no scaling, in which case it acts as a very good temporal AA implementation. FSR2 can be used with any arbitrary resolution scale, including 100%, and also includes a quality temporal AA solution; generally not as good as DLSS/DLAA, but miles ahead of the simple post-process AA that Elite: Dangerous has.
The problem with Elite: Dangerous is that the older version of the Cobra engine it uses has no provisions for any temporal AA solution. It would take significant work to integrate TAA, DLSS, FSR2, or anything else that relies on the motion information that allows them to work.