Although the sentiment comes from an honest and honourable place, the idea that 'practice makes perfect' is a fallacy and the true master understands that perfection is unattainable. And so we are left with the truth that practice makes 'very good'.
You can never prepare for every eventuality in your practice, you can only experience as many as possible in years of accumulation. The masters we know today have prepared for and have experienced the highest amount eventualities and so they perform to a better standard armed with this knowledge.
They are not however, perfect. And though others comment that their execution of technique was 'perfect'; they, being a true master will not let such compliments disrupt the never ending chase that occurs between a masterful practitioner and the perfection of his style.