@Alrange: That's almost definitely not the joke. This one's aimed pretty squarely at an artist audience.
Among those of us who have attempted art, there is a notable tendency for a drawings to become distinctly "worse" in the latter stages of development when it's supposed to be be getting "better"—most singularly, as here, at the stage of paring back and refining down from messy sketchy details to the actual thing.
Artists who actually succeed learn to cope with this one way or another, but at least from what anecdotal evidence I have at my disposal, the syndrome itself still persists for many.