That billion dollars had to come from somewhere, and it definitely didn't happen from a single individual's hard work. A lot of people were involved in that over a long period of time. It's also weird to attach an emotional term like "earned" to that. You can say someone passively earned income, or an investor earned a return on their investment. That's clearly not the same meaning AOC implies when she uses it. So, yea. I'm pretty sure Graham and AOC are both talking past each other.

> That billion dollars had to come from somewhere

When you create a valuable thing, you can use it as collateral for a loan. The bank literally creates the money to loan out out of nothing. When the loan is repaid, the money is destroyed.

Think of a dollar bill as an "IOU $1" (which it pedantically is), and it'll make sense.