A million downloads, commercial deployments by 3rd parties, and basically no contributions coming in. The status quo of the open-source model. They should start selling it to companies to finance their own work on it. Or encourage others interested in static analysis to do the same.
5 of them are over a year old. Most of them had no review by the development team, and many of those that did, got stuck on Bill, for instance, trying to get Travis enabled: https://github.com/findbugsproject/findbugs/pull/48#issuecom...
There is no incentive to contribute to a project in such poor shape.
SonarQube abandoned FindBugs mainly because it was low on activity:
"FindBugs project activity: The activity on the project is quite low and thus the value coming out of it does not come fast enough to satisfy our users."
http://www.sonarqube.org/sonarqube-java-analyzer-the-only-ru...