I have the opposite problem that many here probably have. I built a piece of software that was originally intended for myself and a handful of clients. I'm rather proud of it and it works very well for what it is designed to do. It seems that one of my clients was pleased with it too, because I suddenly got a huge influx of traffic to both my personal site and the associated GitHub account about 9 months ago. I'm assuming they advertised it somewhere. I received many comments about the project, received new feature requests and even a few pull requests. Overall, I was pleased with the moderate amount of traffic and interest, but didn't do anything to actively encourage it. I also picked up a couple new paying clients, so that was good too.
About 6 months ago, a number of users (not my paying clients) started making demands for faster response times to feature requests and bugs. At one point there was an organized demand posted on GitHub with changes "the community" wanted to see in the project. I attempted to engage with the group, but the response of "this is mostly a personal project built for a few paying clients" was poorly received (to say the least). I encouraged users to fork the project and make improvements as they saw fit. The project is licensed so that they can do so and changes need to be available. Again, this was poorly received.
At this point, I'm disgusted with the "community" that has formed around my project. The non-paying users are rude, obnoxious and demanding. The paying customers continue to express, at least to me, happiness with what I provide to them.
How can I discourage the user base from growing and instead drift away? I do not want to drive away clients or potential clients by being down right rude and I do not want to abandon the project, because I utilize it daily and continue active development. I really just want the "needy" users to leave.