Work for a company because you like your coworkers, the work is rewarding, and the pay is good. If you're getting what you need from the first day, you can never be disappointed by broken promises.
These numbers seem somewhat high to me, but this could be Silicon Valley bias (arguably still valid due to our tech startup hub-ness).
I don't think there are enough intangibles to compete with an extra $50k and/or the inverse of 70% of my current salary. However, since I work at a startup, I also believe that such salary gaps don't exist, except maybe at the junior end.
Before the current recession (became obvious), I was at another company trying to lure a network engineer friend to come work for it. The intangibles, including working with me and not being in the Sales universe, were worth, at most, 10%. 30% would have been laughable if not insulting. He took the chance, but, since then, suffered a salary cut and my departure. My bet is they won't be able to keep him much longer, even if salaries are retroactively restored.
What has struck me about senior managers at a number of startups, especially very early-stage ones, is that they underestimate the effect of the intangible of risk on potential (or even current) employees. It can be a doozy and that's what all the other intangibles, including equity, balance out.
Personally, my situation is quite compatible with risk, and I've been around the block more than once with startups of varying sizes and levels of success. Even so, I'm only willing to "do more,"[1] not get "paid less." After all, with notable exceptions, the whole point of the exercise is commercial.
It should come as little surprise that this is the essence of the advice my parents gave me, having been veterans of the local semiconductor industry. I pass on this advice and live by it myself.
[1] A longer commute, flexible schedule (which can work both ways), being on-call, even doing less palatable work, for example. Notably excluded is working excessive hours, since there's little, if any, evidence that it can increase productivity, except in the very short term.
For me, that pretty much says it all.
My two biggest complaints over the years have never been about money, markets, or changing the world. It's always been about what I'm working on and who I'm working with.
I've always thought that if we could just have those two things, we could figure out how to get pretty much anything else. Nice to hear I'm not the only one.