While I totally get that the future is always uncertain, I think past actions of myself and our management team (which also includes employees) speak a lot for how we are probably gonna do things in the future. Our philosophy is called Optimizing for Happiness, because we try to base our decisions on what is best for everyone's happiness, even if it means to sometimes make less of an profit as long as the overall profit is still positive.
It's difficult to explain how we do things, but to give you one example of the past. We had always very successful quarters, except of one where we couldn't pay bonuses. In that quarter people did not complain, but also offered us to voluntarily work less (and get paid less) to overcome this situation. In the end it didn't come that far but I highly appreciated it. And I think this can only happen if it's a give and take from both sides and everyone genuinely caring about each other.
If that's not embodied in contract then it's, regrettably, close to worthless. Companies change, managers change, leadership changes, philosophy changes, contracts only change when they're renegotiated.
In my experience it doesn't.
Soon the company is too big to known everyone, new managements and leaders emerge, whether you want it or not.
There are a lot of people joining in a growing startup. They will outnumber the current employees quickly and shift the current culture with them. Startups change in all aspects, very fast
Compensation doesn't have this problem. You can't offer me $160k and then pay me $120k six months down the road. I mean, you can, but not with a straight face.
The soft benefits you described are one CTO/manager/investor change, or engineer bus accident, away from vanishing and it's not looked at the same way as cutting pay, furloughs, and things of that nature.
While I want to take one of these "work to live" jobs, I always end up taking the salary. I have a much easier time carving out a bastion of sanity in a given company that doesn't advertise the benefits, than to take a significant pay cut along with the risk I just described.