Even if storage were unlimited, artist time to generate assets at higher detail than before increases (advantages of no more work on LOD aside), so it's not clear what's the practical limit. Technically it's storage, cost wise it's still content creation.Fun thing about the Engine reveal demo on PS5 was, that they heavily reused assets all over the place. Just like the portal that was made of parts of buildings etc. just scaled down in size. So it really seems that they are really aware that all this new stuff has a cost in form of storage requirements.
ML can do 2D images of faces, but 3D models is still a problem afaik?In my opinion the primacy of "original captured assets" is just a phase. AI techniques are already good enough to generate faces, why are rocks special?...
I have seen lots of good results on TL based terrain generation. Those were 2D hightmaps as well.
I'm pretty convinced ML will help content creation, but so far i have not seen much practical tools yet, and doing it on client to help the storage problem sounds very distant. Unpredictable results due to HW dependent floating point results alone already sounds a though problem.