> 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.

Note that you should never buy raw cells from Amazon. They are always fake or under-spec. At the very least, this seller claims "Multiple Protections" when this is a fully unprotected cell.

Distributors usually won't sell to regular consumers, but there are specialized retailers who base their reputation on selling quality goods, usually to the RC, flashlight, and vape market.