> what would it look like to directly sell EV batteries to consumers? what would have to happen?

It looks like this: https://www.amazon.com/JESSY-3-7-Volt-Rechargeable-Battery/d...

These cells aren't special, they're all off the shelf designs. The 4680 got some marketing spin, but really it was just a bigger form factor with a tweaked chemistry that apparently just didn't work out. And of course that means you can meta-spin the failure as "supply chain collapse", etc...

Obviously, no, you can't just buy a bunch of 21700 cells and stuff them in the car yourself, the balancing and calibration needs to happen in an integrated way and that repair (digging into a 400V DC battery!) is just way too dangerous for amateurs. But the batteries themselves are mature technology and kinda boring.