09-08-2012, 02:22 PM
dlcache serves as a cache for downloads, not as a map library. It collects maps so that you don't have to download them multiple times. It keeps everything because recorded demos only work fine with the right map version. Besides, not every server uses the same version, and some servers use unique maps. Since there is no centralization for maps, it's kind of difficult to have an elaborate system to manage maps and keep them up to date.