Indeed it is one of the paradoxes of art that structure, form and convention liberate the artist, whereas openness and complete freedom can be seen as a kind of tyranny. Mankind can live free in a society hemmed in by laws, but we have yet to find a historical example of mankind living free in lawless anarchy. As Auden suggested in his analogy of Robinson Crusoe, some poets might be able to live outside convention and rules, but most of us make a hash of it.
Reminds me of a Nietzschean aphorism:
It will be the strong and domineering natures that enjoy their finest gaiety in such constraint and perfection under a law of their own; the passion of their tremendous will relents in the face of all stylized nature, of all conquered and serving nature. Even when they have to build palaces and design gardens they demur at giving nature freedom. Conversely, it is the weak characters without power over themselves that hate the constraint of style. They feel that if this bitter and evil constraint were imposed upon them they would be demeaned; they become slaves as soon as they serve; they hate to serve. Such spirits – and they may be of the first mark – are always out to shape and interpret their environment as a free nature: wild, arbitrary, fantastic, disorderly and surprising. And they are well advised because it is in only this way that they can give pleasure to themselves.
You know what else this topic reminds me of? The band Morphine, one of my absolute favorites. A drummer, a baritone saxophonist, and a vocalist playing a two-string bass. And yet, and yet, within those almost-claustrophobic confines, some of the most deeply enchanting music I've ever heard was created. Boundaries enhance creativity, in art and in life in general.