Can you elaborate on 'fair weather soldier"? As employees of a company we are not soldiers we don't have to obey orders. It would be irresponsible to stick it

Can you elaborate on 'fair weather soldier"? As employees of a company we are not soldiers we don't have to obey orders. It would be irresponsible to stick it out at a company that is going to flame out. If the option is work in a horrendously stressful environment with no real upside vs get another job that is as equally rewarding but more stable and less stressful that is a no brainner to me. I previously was a startup were we worked very long hours over a prolonged period of time trying to turn the ship around. Unfortunately we didn't succeed. Yet I look back at that and don't feel like it was a positive experience where we could collectively feel good about our exploits. I saw what was going on and decided to try and work through it. Yet hindsight being what it is I don't foresee me making the same decision if I find myself in similar situations.