Too quickly compared to what? How long do we have to wait before something's declared "art"? Not claiming this particular graffiti is art - it's rather uncreat

Too quickly compared to what? How long do we have to wait before something's declared "art"? Not claiming this particular graffiti is art - it's rather uncreative compared to Banksy and other such clever artists - just wondering who decides, and how. Also, good for Mark Jacobs for his elegant response, and for trolling the pretentious.