It's my understanding that Generative AI and AGI are not the same thing? Also, AGI has been used far and wide for "Adjusted Gross Income", which everyone who files their U.S. income tax return deals with, it's always what I think of first when encountering it.

Right, AGI is "artificial general intelligence" and refers to what AI used to refer to. The term exists to distinguish between a theoretical human or skynet -like AI and the current models that work within a specific domain after they co-opted the term AI for the common person.