Earlier quoted context omitted.
You don't need to deliberately create silos in order to secure a project. We've had people working on top secret projects and while people may not have known the specifics the company was kept up to date on the progress and outcomes of the project. We brought people in from other teams after an extra vetting process and additional NDA specific to that project.
With industrial espionage, NDAs aren't going to cut it ...
I will grant you, the specific case of TSMC is definitely in the rarer case where there are true tech secrets.