No, I think it's that most people can't afford to work for free for months at a time, and very few people are born into the kind of VC connections that make that a positive-expectancy move.
For people who don't have EIR gigs to go back into, startup failure is really unpleasant and can take a long time to recover (career and savings-wise) from.
Moments later edit
And who are these people with the "EIR" backup plans that you're thinking of? The "EIR's" I've met have all been former successful founders who are simply being effectively pre-funded. That's not some class privilege; it's an additional perk of having won in the past, and it's not one of the bigger perks.
My point was about teenagers trying to figure out what to do with their life. I came to Silicon Valley from another country with no connections and definitely no means from back home. Obviously part of being an entrepreneur at a young age is being able to deliver enough value to an employer to always land back on your feet.
That's not what's holding somebody who has been told throughout all their life that they'll never accomplish anything back, though.