And I would tend to agree. But I would also suggest that those reactions might at the very least give us an idea of whether or not we're facing the right direction. At the very least, it's worth considering.
And I would tend to agree with your original assertion that allowing a subjective reaction to act as your foundation for anything leads to genres being way too mouldable to how a particular audience is feeling on any given day. That's not to say I don't agree that reaction can play a part. (After all, I'm cheap and easy, I like to make my audiences smile, beyond that I lack the talent.)
That opens up a few questions from me personally. Would you consider film an art? What about theater? Comedy? Rock and roll?
I would consider anything an art that can transcend what it is to speak on a higher level. Music, of any kind, theater (which is the art of performance in my opinion) film are all arts. My reasoning being (and it may have some holes in it) that through music you can create imagery, fundamentally affect mood according to the exact design of the piece and its composition. (I don't know of many people being moved to tears by a magic trick for reminding them of a lost love.) Film can provide a message beyond the basics. It can create heroes in people's heads and villains, and allows people to live through something else and imagine for one second etc etc etc (insert more artistic justifications here.) I could repeat this exercise endlessly, but there would be little point. You should get the gist of what I'm aiming at. If not, I apologize.
As I write this it occurs to me that I consider magic to be something like juggling. (No I don't flourish!) What I mean by that is, I may recite a poem whilst I'm juggling, and people may think, great poem. I may tell a really interesting story, or crack a joke, all of which may make my juggling more effective, but in essence, juggling is juggling. I can make my juggling better by adding verbiage that makes it seem more than it is, but I can't make juggling transcend what juggling is. I can't move someone in any real way, nor can I argue intense self development (a la a martial art) through the act of juggling.
Magic is somewhat similar. One can create astonishment, maybe momentary belief in real magic, which will be quickly dismissed and rationalized. I can carefully script my patter, work on it again and again and again, add things that make the trick more effective. Maybe tell a story, or a well timed joke, all of which is polishing a magic trick, however I cannot make a magic trick transcend what a magic trick is. Sure if I find a suitably gullible individual I might convince them that I am in fact magical, but to be honest that's not my goal, and I'd feel a bit uncomfortable leaving someone with such a ridiculous impression as magic being real. (One can scarcely imagine whether or not its positive for someone to believe they met a real magician, though it may be the ultimate goal to do the impossible, convincing someone that you are in fact magical, is unlikely to help them in a long run and to my mind crosses a line. Anyone that believes in real magic must have a fair amount of mental instability to begin with.)
I saw David Copperfield in Vegas over the New Year and his show was great. Smooth and nice. His patter was well scripted and thought out. His performance was well timed etc. I can appreciate all of that, however it did not move me beyond the innate capability for magic to move. (I.e. Astonishment.)
In the same way juggling for me is impressive, I think....wow, but however much window dressing is put on it, it to me is still juggling, and can't move me beyond what good juggling always creates. A wow factor, but I'm not going to be taken back to a time long forgotten, or be reminded of an experience which emotes me through juggling. It by definition doesn't speak to the true human experience, as it cannot do so because of what it is. (Much like, in my opinion magic.)
Magic for me falls into a similar category. Though as I reflect as I write this, it occurs to me that striving to make magic more of an art form, doesn't damage magic. If it results in people putting time and work into the act of performing magic rather than practicing sleights alone, then the idea is a good one, whether I believe in its veracity or not.
And in answer to one post here, there is nothing wrong with a "as long as they are entertained" attitude. To be entertained by magic is no mean feat. I can watch a thousand people performing Tivo 2.0 and think....bleagh. Yet I saw one guy perform it on the street with some fantastic performance, and a great plot and some spiel about quantum entanglement and I thoroughly enjoyed it and was entertained by the performance and hung around to watch more. Some people nearly fainted, and some people were like....wow....great trick. David Blaine (believe it or not) does have the same reactions from time to time. He toured the UK once and got some very....yeah good trick reactions. He just publishes the amazing reactions, but you're not going to get those all the time, and that doesn't necessarily make you a bad magician, you're just looking for subjective people to define your act, and that's not always a good thing.
If you do believe that magic is an art form, then it is a form of self expression, thus you must express yourself when you perform, not someone else's idea. If people like it great, but if people -appreciate- it or -respect- it then that is the goal of an art. Once again....performing magic to an empty room to be true to the art but failing to entertain people doesn't make it magic at all.
Thus to my mind, the foundation on which magic is built is entertaining people through astonishment. You may be able to dress that up and approach art if you believe magic is capable of this, but if you fail at it, nothing else you do will matter.
It occurs to me that I've gone off on a waffly tangent here and can fairly say that this became just my personal thoughts on magic as an art form in general, and isn't directed at anyone in particular.