If you look at the discussion this statistic has started, it's basically a pissing contest of more and more extreme means that either help or hinder one's ability to move. But both sides of the argument are total strawmen: a vast majority of Americans can cover a $500 expense. Most people can find a way to move if they really want to. Those who can't are likely people you wouldn't want to hire.
People were asked "If you had a sudden $500 expense, how would you pay for it?" with options like ["cash", "checking account", "credit card", "pay-day loan", "borrow from family"] and unsurprisingly many people said "credit card". This then got repeated and reported as "Americans can't pay $500 without going into debt".
[0] https://www.federalreserve.gov/econresdata/2014-report-econo...
When an able bodied, single, mentally competent and healthy young person says they don't have enough money to move across country it is actually code for "I have no initiative so I will sit and cry like a pathetic child." Meanwhile people are successfully walking across the Darien gap and the Sonoran desert with entire families to find success.
Might want to add 'male' to that. I'm a female with a damn high risk tolerance (I worked third shifts in major cities, lived alone in one of the most dangerous cities in the country, and had no problem walking alone in a Middle Eastern country where I didn't speak the language well) and I wouldn't hitchhike. And I definitely am not sleeping in a train yard. So that cuts out half of Gen Z right there.