[Zig]

Oh dear, I think my jury would be out a long time on this one matthew! Just a few scattered and unsynthesised thoughts:
If art's "function" is to reflect life, then I'd reckon that documentary photography has every right to be included as art, as indeed every other "area" of photography.
Nowadays, what is considered art does sufficiently reflect society's desire to enthrone mediocrity and obsolescence: tenth-rateness and self-deluding pride has conned and lied its way into the space hitherto occupied by excellence. Thus, like the Emperor's New Clothes, we are expected to have a reverence for utter tripe just because the great and the good tell us so, whereas what we are viewing odes not actually exist.
We are fed so much delusion that we believe it: I know of many "musicians" who don't actually play an instrument or possess any musically creative sensibility; I recently left a "bohemian/poetic" circle in a local town as the "poets" were not imbued with any form other than a nihilistic "performance"-style doggerel; I see daily work by self-styled professional photographers who have no knowledge of their camera, and certainly none of what light actually does, and even less of form and composition.
"Art" is what an artisan does; that is, there should be a degree of craftsmanship, hard work, innate skill and a period of apprenticeship in which the "artist's" focus is on pursuing excellence in doing the best (s)he can, exploring the media (s)he uses to achieve this.
I'd guess the person who thinks of themselves as an artist almost certainly is not, yet they may believe so...they may even succeed in parrotting this so often that others believe them too, yet they are liars who have enthroned self-aggrandisement in the place of reality.
Traditionally, I suppose, there'd be an expectation that beauty is present in a work of artistic excellence: this beauty would only be attainable by the combination of innate skill, hard work, craftsmanship and a period of patient and humble learning.
I'd offer that beauty thus has been usurped from art for no other reason that hard work, patience and humility in learning are all considered anathema to quick-fix addicts who want to be seen as skilled immediately. I'd also offer that their egocentric, babywhining voices have all combined so noisily that society would rather nanny them by giving them what they cry for rather than what they and society actually need: tell them they are good and that they can be excellent if they have the right kit and the right money.
I plump for(said he) classical parameters here: art must have beauty, clarity, harmony, form and radiance, regardless of the expectations of others to water these down(good enough for Thomas Aquinas, good enough for me: Joyce devotes loadsa time to this in Portrait of an Artist, by the way, if ya need a reading-list; chapters 3 to 5 has the main exposition).
Don: art IS practical, that is the point of artisanship; it reflects life whilst commenting on it; heck, great artists have successfully captured and reflected the spirit of the age, the "sitz im leben". They would, though, have been laffed out of court for being charlatans, had they demonstrated poor control and less than mastery of their craft.
Must go and have a cuppa...shagged out after a long squawk!