Also, Bell Labs wasn't a university, and Thompson and Ritchie were not tenured lecturers. They wrote assembly code, not papers.

They wrote papers too (Bell Labs was, after all, a research lab), took sabbaticals, and lectured at universities. I think one of the group (Kernighan?) took a sabbatical at Berkeley that was one of the events that gave rise to BSD?

UNIX was academic, because Bell Labs were forbidden to make profit out of it and thus licensed it via a symbolic price to universities alongside source code tapes.

Had Bell Labs been allowed to sell it, and history would have turned a very different path concerning UNIX clones and its adoption.