Yeah, I think staying at a big company is a proxy for a few things that can work against entrepreneurship: risk aversion, used to "playing a role", divorce of your daily thinking from the marketplace... It's like at BigCo you become a specialized, mature cell. Startups require stem cells, ready to adapt into whatever the market requires.
I'd imagine that the number of successful entrepreneurs that couldn't find employment if they wanted to is pretty low. Personally, and from what I've seen, entrepreneurs and self-employed people just really really don't like working for 'the Man'. Even if 'the Man' is a great employer.
The part about being holed up in an apartment resonated with me. I worked for a startup in the valley and then moved to India to start a new company. So being in a place where running a tech company is not the default is a lot of friction!