I thought about it poorly initially. I modeled it simply as pay drop for a learning period with greater exposure to the whole thing (I tried building out one arm of a company). In my case, I should have just founded at the time.

A close friend of mine actually helped. The short form is: I'm in my mid-30s, so the majority of my compensation and wealth is still in my future so long as I can keep the engine running. So I optimize to keep the engine running. Some time that may be a couple of years in big tech so you have the amount of money that removes financial anxiety from your life. The rest of the time that may be years in startups because big tech is a low productivity environment.

This may be different for you, but I don't want to stop working so so long as macro stuff stays sane, I will probably be doing things into my 60s. That means that endurance is more important than power.

If you really believe in that startup and did a lot of research that suggests that the startup will boom and grow as much as you think it would, it is worth accepting the lower pay. On another note, a high paying company is always the same, it is basically a stable job without much adventures or financial upside in terms of stocks.