ARPA/DARPA history of the net could have been fleshed out a bit further given its seminal importance, defense, RAND, etc

Seems a tad like Treehouse authors wanted to sanitize the birth of the net. At the very end of this series Joy mentions US Defense Dept. It's important for young students to know how US Dept of Defense (DOD) and ARPA or DARPA (as many know it essentially stumbled onto the creation of one of the 3 or 4 most significant milestones in human history (e.g. agriculture, steam engine).

Discussion of the debate regarding whether or not original purpose of the Internet was to ensure communication during nuclear war / catastrophic network loss might have been helpful.

This is a fascinating topic, and individuals, in my view, would be empowered by more deeply understanding how and why the net is as it is today (particularly give credit where it's -> US Dept of Defense, luck, and fear).

Wikipedia: According to Stephen J. Lukasik, who as Deputy Director and Director of DARPA (1967–1974) was "the person who signed most of the checks for Arpanet's development": The goal was to exploit new computer technologies to meet the needs of military command and control against nuclear threats, achieve survivable control of US nuclear forces, and improve military tactical and management decision making.[27]