At the risk of misinterpreting what you're getting at: the lesson to take from NSB is not "Don't switch languages" or "Switching languages is ineffective".

At the risk of misinterpreting what you're getting at: the lesson to take from NSB is not "Don't switch languages" or "Switching languages is ineffective". The lesson is: "Software development is inherently difficult; don't expect that to change just because you switch to a better language." Brooks readily embraces and promotes the idea that better languages are vitally important, to strip away complexity that isn't strictly necessary for the already sufficiently complex task of building large software systems.