alt Hacker NewsHere's another: code was open sourced with every intention of becoming a thriving community-driven project, but in practice users only take from the code what they want for their own needs and never contribute back, or expect the maintainer to solve all of their integration issues for them. Eventually, the maintainer decides that they have better things to do than fixing other people's problems, and that there is more value to be had from bespoke contract work. Some updates still get pushed but over time the project gradually gets abandoned and the open source dream slowly passes away.
It sounds like the maintainer you're describing was underhandedly helping their users with the silent expectation that they also contribute back to the project and got bitter when it didn't happen that way.
Open source is altruistic, remember. You explicitly tell the world that you are happy for anyone to only take from the code what they want for their own needs and never contribute back. If you don't want to help users or develop your software alone, an alternative is to sell the software and support service to users and use the money to hire developers.