I've written a handful of plugins which were written 2+ years ago, are very simple, require no updates, are still 100% functional today. But they've been removed from the plugin listing because they're old, haven't (required or) been updated in 2+ years.
I've just spent an hour or two going through and bumping all their versions to 0.X.0 so they're back in the listing. It would be nice if the system was smart enough to recognise when a readme.txt was updated to say the plugin is compatible with 3.4.2, that it's "maintained". Now any users of my plugins will be given an update notice for no reason other than getting the plugin back into the directory.