because there are less items around than ever before, and theres NOTHING to do. if the server was reset, the same quantities of event items could be released as before (im sure staff doesnt want to release "long lost items" and then have the old ones turning up again). and all the ****ty little things all over the place would be flushed out, i cant give any examples for that point but just imagine all the clutter and bs
edit- actually i got an example for the last point and can explain in one word: bugs