An important factor is how much you feel in control of your fate (whether the control is real or imaginary is less important). Tech startups feel it's much more up to their skills and creativity to make it than a lowly employee working for the Man in a big bureaucratic multinational, even if statistically they have about the same chance. It's similar to why most people are more afraid of flying than driving, even though the former is much safer statistically.
A tech startup analogy is: a company issues an IPO or gets acquired.
You know it's a fairly rare event, and it may not happen to you, but you believe it's possible, so you're motivated to keep going.