Over at WP at every new version release, plugin authors receive an email with a list of their plugins and the question to simply update the
readme.txt file to reflect that the plugin is still valid for the new WP version.
Depending of course on the number of plugins an author has to its name, those should take no more than a few minutes of one’s time.
However there are still many many plugins whose authors cannot be bothered for some reason.
In the WP Plugins Directory the plugin that has not seen an update for more than two years, receives a warning.
I would like to propose to have plugins that do not receive regular updates removed from the Plugins Directory.
Of course this needs to be a bit further nuanced, because there are plenty one-liners out there that really do not need anything else. In such cases the plugin should however receive an update when a new ClassicPress version is released.
In case of plugin removal, it would be great - but I am not sure if that is possible at all - to release a version of the plugin that warns the users that have this plugin installed, that the plugin is abandoned and to suggest looking for an alternative.