It's possible to be smart and be a one-ply thinker.

It's possible for onlookers to be wowed by how plausible the smart person's quick analyses seem on so many different domains, but on each individually they're only single ply.

Sarumans are one-ply thinkers mostly.

Radagasts are multi-ply thinkers.

Just because someone is a virtuoso in detailed one-ply thinking in novel domains does not make them a multi-ply thinker.