My family does the exact same thing, except a bit faster. My sister already went to college. My relatives are business owners of nail shops. Granted it's a only a single anecdotal point.
Beside, startups founders plunge automatically to "poverty" level just so they can start their own business and then rise to millionaire status or more if they's successful.
To do a startup, you have to be middle-class, at least, from the start, because otherwise you have no hope of getting the funding or building up the savings.
The most successful startups are an exception to the fact of American society being tiered, but these types of sociological statements always admit exceptions. If you want to see our tiered society in action, note how difficult it is to get venture capital and press coverage if you're not from an upper-class background, and compare it to how easily rich kids are able to get these resources.