I'm not quite sure what you mean, but if you can't reduce the size of your position without losing your shirt, you're not really winning; and if staying in your position requires you to put up more money than you can raise, you've hit the limit I was referring to. No one can expect to keep finding money to support their trades until they turn profitable.

EDIT: Maybe you mean that they didn't try to make a larger bet after they got in trouble? But whether they needed to make a bigger bet or whether their existing bet was already too big, it's still the same issue; the only way to avoid liquidation is to expand the use of credit, which hits a limit at some point.