We will never know exactly why people make art a part of their lives.
Sure, we can ask the question.
Sure, they can answer the question.
But we will never REALLY know.
People attend art for a lot of reasons. Some they are able to state, some they aren't able to say out loud. Those reasons change over time. The reason that they attended your book reading in November may be ENTIRELY different from why they attended your reading in February.
So don't bang your head against the wall trying to figure it out. Instead focus on creating experiences that will appeal to what is universal.
People want to feel like they are a part of something important.
People want to feel like they are a part of a community.
Can your art appeal to those universal desires?
If it can then you'll always know why people are coming.