> For that matter, once we weren't on Unix but rather on the PC, and we had a nicely-modified Pascal (Turbo Pascal), why did C/C++ win there, too?

Turbo Pascal was quite successful in its day. But Microsoft chose C, and the rest is history. Absent Microsoft's decision, Pascal might still be around.

If you look at early Mac development, for instance, Pascal was actually preferred. C only ended up winning due to being better known, which was a result of the critical mass of programmers trained on Unix and Microsoft's offerings.