People are mediums themselves.

Good point. One corollary consequence of the assertion that the medium is the message is that if you want to change the message, then you change the medium.

I'm not in favour of or against any ideas in regards to art. I like to explore all options myself. In the environment that I used to be, members emphasized practice over theory. There was a lot of theory at the higher level, but the focus was the actual development of the "art". Oftentimes, theory would just collapse in the face of a broken wire, buggy code, or misbehaving sensor. There's also the issue of human nature. Some art required human participation and humans can be unpredictable. So far no theory can help us predict what they will do. A recent art installation proved this very point, as you can see in the following video.