Onur Cobanli explains:
This is not a mere opinion, it is a fact due to regression to the mean, it is about standard distribution. The reverse of this quote also true, half of the designers have less than average IQ. You might say that no, designers are creative and it does not make sense but I must disagree. This is because designers are not necessary extraordinary people, indeed they are mostly ordinary people accomplishing extraordinary results by spending considerable amounts of diligence and effort on their works to make intelligent products.