Based on things I've read and seen (ie. just a hyphothesis), I believe there's a big dip in creativity as artists increase in learning. I think this is one source of the common (but mistaken) idea that education inhibits creativity---because most people and artists stop actively learning about their craft before they reach their creative and expressive potential.
Also, I put in the red graph for anyone who happens to be amazing and never experienced a dip. You are awesome, and you really shouldn't waste time reading my blog. Unless you are part of that elite group of people who are still in the dip but don't realize it (we all know one or two).
This graph illustrates my hypothesis that after the big dip, if an artist continues learning, comes a leap in creativity and expressive ability. The key to reaching that point is pressing through the dip and not assuming that you already know enough.
Image Credits: Some kids, a Disney Artist I couldn't track down, Frank Lloyd Wright, Luc Desmarchelier
I separated expression and creativity because I think expressive ability never takes a dip, but it is accelerated as creative ability is unlocked.
Also keep in mind that this is all learning, not just learning construction---although construction is still the foundation for expressive learning. This graph doesn't represent any particular period of time, and can actually happen multiple times over an artist's development (ever experience art depression? You're probably at the bottom of the curve and just need to press forward and try to learn more.) An artist can also simultaneously be in different stages of the graph for different abilities---e.g. very creative architecturally but not as creative in designing creatures.
Also, I put in the red graph for anyone who happens to be amazing and never experienced a dip. You are awesome, and you really shouldn't waste time reading my blog. Unless you are part of that elite group of people who are still in the dip but don't realize it (we all know one or two).