More importantly, they have made virtually all of their lifetime profit by that time. Rare exceptions and that tiny remaining dribble are weak justifications for longer copyright terms.
I think AI/ML will be a forcing function. More new media will be created every year than all of recorded human history.
They copyright office will cave under this pressure. They'll either say none of it can by copyrighted, which will be complicated -- who wants to prove which parts were AI-assisted? More sensibly, they'll just contract the copyright TTL. That's easy to calculate.
If this happens, it will have very interesting implications for Disney, Universal Music Group, et al.