Even big corporations that have contractually committed credit facilities have had banks shut those down during times of crisis (basically saying “sue us” to the borrower) so no matter how solid the ability to borrow may appear, that kind of thing has a tendency to evaporate in a moment, just when it’s needed most.
I have credit cards with a ridiculous aggregate credit limit, but in another 2008 scenario, anyone want to take bets on how long those credit limits stay high while unemployment is on its way to 14%? I would prefer not to.
And regardless of earning potential or useful skills, the owners and managers of for-profit enterprises are going to be belt-tightening at the same time (out of necessity or caution or simply by never letting a crisis go to waste) and their appetite for bringing on a new entry level employee will be limited - just at the time the rest of the system is grinding to a halt.
Someone in their 20s without significant financial or familial obligations is generally going to be well situated to make it through one of those crunches, but it doesn’t take a whole lot to bring the edifice crashing down.