I was going to say the same thing. "We'll take care of you" is simply not a promise that startups can make. You might work your ass for them for a year at a below market salary, only to see the whole thing tank.
True, or to be laid off if you're considered 'too greedy'.
Let's not forget your employers had this great idea and you should be happy to be honoured to contribute to that great idea. After all, you're jut a code monkey.