Wow I would not want to be in a 6-month crunch let alone longer. Besides the human toll, frequent (or perpetual!) crunch(es) are also bad for the codebase, and

Wow I would not want to be in a 6-month crunch let alone longer. Besides the human toll, frequent (or perpetual!) crunch(es) are also bad for the codebase, and not only in "burnt out people are not productive and instead produce bad code". In addition, the code never gets cleaned up and all those temporary workarounds become permanent architecture choices. Everybody knows it's bad but there's no time to go back and fix it. That is, crunch makes not only adds to tech debt, it's like "tech debt go brrrr" (to borrow an inflation meme).