The layperson doesn't understand creative professions, because what creative people do is a luxury, not a basic physical need. Everyone needs a place to live. Everyone needs good health. People don't need television shows or amusing cartoons in the Sunday paper... do they?
The need creative professions fill is not a physical need, so the physically-minded masses don't value these careers as much as they do doctors and lawyers and accountants. But they want what creative people do. It enriches their lives. It makes them feel things.
Creative professions put people back in touch with themselves, open their minds to new ideas, give them distractions from the rough spots in life. A society risen above filling basic physical needs can focus on the higher, mental, spiritual, and emotional needs so often left unfilled. There are some people who still don't understand the importance of this. That's why creative professionals are admired, but not universally respected.
Anyone who knows how complicated the human body is can understand why doctors are necessary and valuable. Those who don't, think doctors are magical and godlike. It all comes down to understanding and understanding to knowledge.
Art is difficult for people to understand because it's tangled up in the intangible, in feelings and impressions, in memories and tastes. The higher a person's thoughts, the more likely they are to appreciate the need for art in their lives. The more intelligent a person, the higher their thoughts. Therefore, smart people value art.
The next time you meet someone who undervalues your work, downplays the need for it, or compares it to their child's hobby, realize the person is likely physically-minded and doesn't see the importance of art in his life. He's also not very smart. Later, you can draw an unflattering picture of him or write him into your novel as a villain.