... a piece of art outdated?...did you even just say that!? We should just toss out everything in the Louvre then since it's older than three years right? Educate yourself on matters like these before running off to complain about them. All the information about DDs, how they're chosen, and the rules that are applicable can be found in the faq's which are at the bottom of every page here on dA.
It's more like if someone sends in a DD for the piece and dA liked the idea, they do it. People send in DDs for the oldest and most viewed pieces all the time. It's a shame when someone who is new and amazing do not get that chance.
Works of art never goes out of date. Just because a picture, painting of drawing haven't been "discovered" within a few month, shouldn't mean it's gonna be lost forever in the vast world of dA's huge memory bank. There are a huge number of unseen, undiscovered gems out there, some years old. Unfortunately, most of them are probably never going to recieve a DD. However, there are other ways to present an artist, if that is what you want. Journal features, comments, groups etc...
Being old should not really matter when it come to DDs. There are some really old art that people have done that are really great. One of my old animation that I did in college had gotten a DD I don't complain about it and it is still one of my favorite animations I have done.
DDs are just features. How does an outstanding piece of art become less outstanding after 3 years? Should the Mona Lisa, The Scream and other artwork be stopped from being showcased around the world just because they're older?
I actually can take this. DD's are supposed to be used to acknowledge artists. I don't think it'd really matter if it's outdated. It doesn't matter to me, it's pretty good art. It deserves the DD anyway.