[pjmlp]

Besides what others already replied, universities were "free"[1] to use AT&T UNIX V source code and BSD derived code until AT&T was allowed to go commercial with UNIX, and suing Berkeley university in the process.

In fact, GCC only got traction after Sun introduced the idea in the UNIX world of selling the developer tools instead of bundling them wiht the OS.

Back in 1994 the Wirth systems were mostly only available at ETHZ.

Had Linux not come up into the scene, with the ongoing BSD lawsuit, and the UNIX landscape would have looked much different nowadays.

[1] - "free" here meaning several factors cheaper than buying a VMS or OS/360 timesharing system for the university campus.