You are discounting equity, bonus and future raises at bigco that you won't get at a startup. At bigco you can get rsus that are worth $25k all of the time, and 200k some times.
That's a good point. I agree, but IMO you can't bank on those. For example, I worked at Google for 3.5 years, got 1 small raise and 2 small refresher grants. At another startup, I never got a raise but got 1 huge refresher grant. Also, OP is talking about a late stage startup, which probably spends more like a BigCo than a seed stage startup.