To validate the argument, you need to take into account the person's current earning potential as well.
Additionally, for the living costs argument, there's some research or studies that quote you need 75k to happily cover your living expenses in the US.
So, for this example, even if person A has low net worth, his earning potential isn't mentioned.
You need to take both of these other factors into account as well.
So A could be a a rookie NFL player who just signed a multimillion contract and B with a 10th year veteran who has $5m but is at the end of his career.
It doesn't matter that A has no money in the bank if he's going to make more in the next few years.