Proposal: When a new app is submitted in a saturated category, poll the oldest N apps for usage and developer activity. If one of them is below a threshold of relevance then mark it for removal and allow the new app to replace it.
This is a really good idea -- I have apps in the store that I haven't touched in 5 years that still get downloads but I have no idea if the app even works any more and I don't care to check
Do people a favor and remove the listing for them.