I'm not arguing with the rule, but one notable exception is Kevin Systrom who stayed with Instagram for years (growing it from 30 million users when the acquisition was announced to over 800 million). He discusses the choice to stay, and the reactions from others in the company, in this interview: https://tim.blog/2019/04/25/kevin-systrom/
But now you mention acquisitions, it could be argued that NeXT CEO Steve Jobs did OK as an Apple employee…