From a technical standpoint that makes a lot of sense. I think the main obstacle there is that Tesla doesn't (as far as I know) actually make LFP batteries. The ones they use in their cars come from CATL. Tesla could just buy batteries from CATL and package them in a Powerwall product, but they might not be interested in doing that since there's a big risk that CATL or some other manufacturer could make an identical product without the Tesla brand and sell it at a much lower price.

There's a theory that Powerwall was just a way for Tesla to not waste their excess battery manufacturing capacity when car production wasn't keeping up. I don't know how true that is, but if so there isn't much of a need for them to figure out how to sell CATL's excess battery supply.