A wave is already what we call a manifestation of a field, maybe I skimmed too quickly but I don't get the author's breakthrough point.

> Now, when I told my editor at Allen Lane about my own interpretation, he immediately said “It’s Many Worlds on steroids!” There is a grain of truth in that, ...

Dude, this is an answer to an entirely different question. He's proposing an interpretation of QM, which is independent from "how many fundamental particles".

A wave is a phenomenon that propagates through a field - i.e. the field is what allows the wave to exist.

(The philosophy of that admittedly gets messy, though, e.g. "are fields real objects?")