"When is the time to let go?"
This goes for all areas of life: intimate relationships / marriages, employment, being part of a hobby club that's not the same anymore, local community help (donations, voluntary labor etc.).
We the people are extremely bad judges of when is the right time to leave -- and 99% of the time we leave way too late. Usually after getting some deep emotional scars as a bonus.
In hindsight (which as they say is 20/20) every time in my life after I left any kind of interaction between me and other people / companies, it was well after I should have. But only in retrospect.
I gradually learned to recognize the signs and started to escalate problems early. And if they aren't addressed, leave early.
Life is too short to keep a death grip on things that are poisoning you. It seems every one of us learns this lesson very late in life.
But don't get me wrong: I am doing my very best not to live with regret and make myself better utilizing those past lessons -- as you said. But analyzing it back in time, I know that I actually had the right mindset but was too weak to utilize it.
Prioritize your health. Go your pace and accept the consequences. Always feel satisfied with your choice.
Prioritizing your health is an absolutely sound advice every time. I started doing that and even if the improvements are small and hard to feel just yet, it still feels great to feel better than two weeks ago.
If you respect me as an engineer, you do what needs to be done to address my genuine and valid concerns. If you can't, I can still like you as person, but you've ceased to be an effective leader. (I hold myself to that same standard with the teams I lead as well. I'm only as good as 9 parts what I deliver and 1 part what I wish I could deliver.)
I think they didn't realize that they had actually found a truly awesome company by chance and were witnessing its conversion to 'normal company'. Nothing more, nothing less. But if you ask me it was still totally bearable. The devil you know type of situation and hey, I'll let them pay me f they keep wanting to. I can still jump ship if they turn from normal company to actual evil (like introducing the kinds of perks that try and bait you into working 80 hour weeks and thinking it's fun and worth it and normal) company. I can still jump ship then.
I have been in that position before - that’s why I’m asking
I stayed 11 years at my previous job because it was fun and we were shielded us from a lot BS.
Sure, it's emotional stuff, and the purely rational actor would dip without question. But having emotions is healthy and normal, even if it means they sometimes lead you to somewhat suboptimal situations. Of course, it can reach a point where people get locked in out of fear of the unknown, just like bad relationships. But it's rarely as easy as just saying "Okay, time to leave."