If a PM ever says "that's not my job" they're not a PM.

The job of the PM is to fill any gap necessary to get to a great outcome.

They aren't just grout to fill in small spaces, they are the concrete to fill arbitrarily large gaps.

A situation may be more or less set up for success, but within any given situation, it is the PM who is the shock absorber, who fills in whatever gaps exist.