I think we've extended the use of the word art too far. In my opinion art is really just paintings and sculptures. Good art involves a lot of skill, eg: years of practice, attention to detail, sophisticated processes, careful choice of mediums, tasteful composition, and choice of subject matter. While a lot of this stuff is opinionated there are definitely rules to a lot of these things. There are essentially guidelines that have log existed for measuring an artists ability to capture color, shapes, light, and movement. Even with more modern styles like van Gogh and Monet these rules applied.
At some point we threw this out the window with the post modern movement and said art can be anything, becoming more focused on the cleverness and profound underlying message that this new "art" contained rather than the skill, dedication, and aesthetics that went into it.