What he meant was that anyone with a sufficiently functional hand as a drawing potential at least equal to that of a "professional". That's not saying that ever

What he meant was that anyone with a sufficiently functional hand as a drawing potential at least equal to that of a "professional". That's not saying that everyone has the same drawing potential since "professional" isn't the limit of drawing skill. And its very likely that learning to draw at a young age is if not orders of magnitudes, then significantly more effective than as an adult simply though greater brain plasticity, and probably having less inhibition.