Why did artists during the industrial age turn away from classicism and develop a different style of art?

They were reacting to the social problems brought by industrialization.

Explanation:

Romanticism and Realism started to become more popular  and they coincide with the era of the industrialization.

Artists who would ignore the social problems became romanticists. They'd focus on the individual and in nature in many ways. This way of thinking was highly criticized by another movement that decided to focus on the problems of life, the realists.