Absolutely. There are plenty of naturally occurring beneficial microbes currently being applied/utilized in US Ag to accomplish this. P is different than fixed N as the P is currently in a plant unavailable form in the root zone ie soil. Microbes solubilize thru enzymatic processes this unavailable P into a plant available form. With decades of MAP/DAP application and/or manure there is an abundance of locked up P in the soil and beneficial microbes hold an immediately accessible set of keys!

That’s a really good point. The article was talking about nitrogen and I conflated this with phosphorus and potassium with my “mined fertilizers” comment.

Potash or "pot ash" can be produced at home with firewood and, well, a pot. It doesn't scale well though. Not enough to meet demand.

Understood, but I also wondered if someone had figured out how to genetically engineer away the need for this element in fertilizer.

Well...since phosphorus atoms are essential parts of DNA, RNA, ATP, and a <cough> few other slightly-important molecules in most cells, that might be difficult. And the humans or livestock eating the crops also need those molecules in their cells...