Lots of people in the US that start companies are well-off, too, and they don't "desperately dream" of escaping their life situation. They just have a very different risk profile, and are happy to risk failing for a better chance at success.
It’s more than a desire for money too. The SV culture simply assigns a lot of respect to founders — definitely to the successful and also somewhat to those who try and fail. The founders I know do this not to get rich but to access that prestige. In fact, most know it will be a financially difficult task. Consider eg the lore of the Airbnb founders having to max out a binder full of credit cards…
For sure, when I said I was an enterpreneur in the US, Hungary and Spain, I got three different reactions. In the US, people think you're a cool kid, in Hungary they think you're a crook and in Spain they think you are poor.
