I noticed that too. The tools principle dovetails with "Use a superior development system". Infocom's game building tool (the ZIL compiler) was originally a PD

I noticed that too. The tools principle dovetails with "Use a superior development system". Infocom's game building tool (the ZIL compiler) was originally a PDP-10 program. LucasArts developed many games using the SCUMM suite of tools, which they developed on Unix-based Sun workstations. (The SCUMM compiler used YACC!) Even today, you can use a compute cluster to render videos, "bake" assets, distribute compilation, run tests, run machine learning, ...