Art is a need for, or expression of, our creativity, but one that is not reached or required or appreciated until almost all other needs are met. It is an indication of an advanced society.
An example of this way of looking at art is using Maslow's Hierarchy of Needs which if you are interested is discussed here.
Maslow puts the arts under 'creativity', at the top of his pyramid.
(Later on in his life he added a further level which he called 'self-transcendence', when he observed in himself that the achievements and success of his offspring were more satisfying than his own.)
Abraham Maslow, A Theory of Human Motivation 1943.