In this AI age I'm seeing it coming to fruition. Fullstacks have (IMO) more potential now than narrow specialists because they can now get away with high-level remarks and letting the AI fill in the details.

Yeah I’d say more specifically that general first principles understanding of different areas and the ability to think about systems / architecture / general logic is very useful.

Unlike traditional polymaths, detailed knowledge / familiarity with APIs and libraries is less needed.