To me it seems like a fundamental motivation - we do art because we want to impress those around us, gain respect, help to attract a mate, make money... Those reasons don't exist without other people to show our art to, and are much less effective if art is too easy to make and too common.
I'm sure there are people who don't have ambition to ever show others the skills they've been building, even in indirect ways, but I doubt it's common... What do you think the motivation is?