Lithium ion batteries are not a single technology and are not static. There are periodic changes that improve the batteries in various dimensions. They are constantly evolving. At the same time, it is perfectly feasible for EVs to switch to alternate chemistries a construction methods. Individual vehicles might not switch but a manufacturer could switch their product line to start using sodium or sulphur or whatever new chemistry comes along.

This Ars story talks about the ongoing improvements to battery tech… https://arstechnica.com/science/2021/05/eternally-five-years...