Art plays an important role in stimulating ideas that reflect later important developments in human history. This entry uses Sigmund Freud's position on the ability of poets to communicate human fantasies in order to understand an artist's role and distinguish it from the role played by an artist's fans in human development. Since much of the discussion concerns the artistic use of language, the term poet' is used, but it can be understood to apply to all artists generally.
In The Relation of the Poet to Day-Dreaming Freud suggests that when people without literary skill or non-poetic people reveal their inner fantasies to an audience, their audience is generally repulsed by this revelation (or at least they remain indifferent to it). It's easy to imagine someone describing their dreams with a series of "I want" statements, which cause that person to become quite annoying. Poets use creative techniques to assemble language, which also reveal the poet's fantasies to his audience. However, a poet's audience is generally pleased with the revelation. So, the creative techniques that poets use to assemble language allow his words to overcome the feelings of repulsion that are felt when human fantasies are revealed without creative literary techniques.
My understanding of Freud is that when a poet and a non-poet reveal the same (or relevantly similar) fantasy to an audience, the poet's revelation will please, whereas the non-poet's revelation has a tendency to repulse. So, even though the same ideas might be found in each of the fantasies and their revelations, an audience is likely to accept one and reject the other.
If an audience is repulsed by a revelation of "fantasy", then the ideas manifest in that revelation (regardless of utility) are at risk of rejection and scrutiny. Thus, pronouncing them creates an obstacle for the acceptance of those ideas by others. This is one reason we generally choose to keep our fantasies to ourselves.
Since poets are more capable of communicating ideas that will be accepted, they are poised to plant the seeds of change, innovation, development, and even enlightenment into the minds of others. Perhaps for a time a poet's words will only be regarded as pleasurable entertainment. Humans, however, are hedonistic creatures. That which stimulates a pleasurable state of mind for us is generally what we seek. So the objects of human pleasure, such as the experience of a work of art, have the potentiality to develop into the objects of human desire, and thus become a goal we seek to attain. However, defining this goal is often difficult because it is often lost somewhere between the act of experiencing art, and the experience itself.
Perhaps human development depends primarily on the ability of a poet to get the ideational wheels of change turning. Whatever the case, it is doubtless that poets and other artists have and do play this vital role to a very large degree. But artists cannot accomplish the task of change all on their own. What is necessary is the sincerity of the artist's fanship. Fans must contemplate the direction that the artist stimulates, and apply it to the situations that life presents in order to promote and protect human development. This task is simple for some and more difficult for others, for it involves abstracting from a work of art (which is itself an abstraction), and developing a practical application of that abstraction.
So, yes, a fan does gain pleasure from going to a play, observing a painting, listening to music, or attending a concert; but there is much more to be accomplished that serves as the continuation of the ideas that are present in art. The effective artist has, in my opinion, completed his part of the bargain. It is the responsibility of the fans to find sincerity in their fanship, and fertilize the ground in which the seeds of enlightened human development are planted. That is what it means to be a real fan. Otherwise, museum patrons, movie-watchers, and concertgoers engage in nothing more than aesthetic masturbation an experience that feels good momentarily, but has no real meaningful connection with our future, and those around us.