I think it goes without saying that absolutist views on work are going to be wrong. If you structure your organization around a work/life balance, you have to been more strategic about how time is used than an 80hr/week "burn-and-churn" organization. The upside is you'll have less turn-over, happier employees, and (hopefully) happier customers.
I'll just say there's one hidden advantage to less crazy hours: it's a lot easier to spot mediocrity and weak-points in processes and teams. I'm not talking about people skill-building for the first time, but if someone consistently needs to work twice as long to get the same output of their peers, there really shouldn't be a social incentive structure in place to reward them for what is effectively poor performance papered over with extra hours.
I'm fairly convinced that there's a bimodal distribution of knowledge work in the world. In software, but not only in software. In any field whereby individual workers can make a significant difference to the bottom line (e.g. it's not commodity work).
People stuck in sick system jobs think that's just how the world is. The managers there are stuck in it too, so it becomes worse. The people who stick around tend to become bitter and think the world is all underpaid long-hours bureaucratic corporate shite.
I figure that the 'middle' path, of jobs that are sort of alright but not actually 'good', doesn't really exist, because there are feedback loops at both ends pushing companies away from the mean.
I have no real evidence for this other than it matching my personal experience and interacting with other people in various circumstances. It's happened more than a few times that I've interviewed somewhere and been offered half the market rate for silly amounts of responsibility by managers who seem surprised that I turn them down.
I made an intentional decision to refuse to work such insane hours about 15 years ago and limit my standard workweek to 40 instead (if there's an unusual situation that calls for extra time, I'll work the extra time of course -- but that's pretty rare) when I'm working for somebody else.
What I've found is that not only has in not harmed my career in any noticeable way, it has improved it in an unexpected way: the companies that really only expect 40 hours per week also tend to be companies that produce higher quality software, have a better working environment, and look better on my CV.
I don't understand how to read Twitter threads. It's like instead of someone handing you a book, they tear up all the pages and throw the pieces at your feet.
I'll just say there's one hidden advantage to less crazy hours: it's a lot easier to spot mediocrity and weak-points in processes and teams. I'm not talking about people skill-building for the first time, but if someone consistently needs to work twice as long to get the same output of their peers, there really shouldn't be a social incentive structure in place to reward them for what is effectively poor performance papered over with extra hours.