Lead acid is cheaper because they are really easy to recycle so in a low tech env they are preferable.
So if you think about the amount of materials - lead acid are almost double the weight vs. lithium batteries per amp hour to start with, then multiply by two because of the usable capacity difference, times four to eight for the cycle life… So you’re talking having to recycle something like sixteen to thirty-two times the weight of the lithium batteries in lead, before the LiFePO4 batteries would have even reached their end of life!
It’s really almost unbelievable how much better and cheaper the lithium batteries have become!