It's true that if you designed a EV battery pack to be one solid anode and cathode, you might have to worry considerably about the chemistry that makes up the pack.

That, however, isn't how anyone is building packs (that I know of). EV manufacturers are all pushing for packs made of modules made of cells. The cells that they are making are quite literally a typical form factor (Typically 18650s)

Yes, you have to figure out how to put together your pack of 18650s and how to cool/heat them. However, what you don't have to worry about is what chemistry goes into them. That's an upstream supply concern. A 10% bump in storage can be gained with better chemistry, it doesn't require that you completely redesign your pack with each new chemistry. As a bonus, that also means you can source your cells from multiple manufactures, because they are all pushing out the same form factor.