The line "even a 60% bettor loses 30 in a row" gets repeated in every betting community, and taken literally it is not true — not rarely, not occasionally, not at all. It survives anyway, because the feeling it points at is real. This lesson replaces the slogan with the actual arithmetic — which is less dramatic, more useful, and still bad enough to make most people quit.
First, price the literal claim
Thirty consecutive losses for a bettor who wins 60% of the time means thirty independent 40% events in a row:
