Even if the penalty costs more than the profit in the cases where they get caught, they'll keep doing it if they don't always get caught. Or if it allows them

Even if the penalty costs more than the profit in the cases where they get caught, they'll keep doing it if they don't always get caught. Or if it allows them to build a hard-to-break market position (see e.g. how Intel destroyed AMD, the fines couldn't undo that).