This is specifically what I'm talking about. Because of some weird patent agreements, manufacturing of LFPs have been confined to China and they've not really been producing a large enough number of them to fill the role of grid storage (at least outside of china). [1]
Not sure how to reconcile "they aren't available" with "starting to see them everywhere".
They're great batteries (especially compared to lead acid) and at least in small quantities, they have been widely available for years.