There's a better way to frame this: Do you think an open source project creates a perpetual obligation? Even if many other developers depend on your project, are you forced to continue or can you walk away? If you assume you can walk away, you can then ask whether it makes sense to stop working on a project. And that answer requires a bit of introspection, being "honest to yourself regarding the intentions".

"advancing the state of the art" is fundamentally different from "money" and "fame" insofar as the latter involve social effects that you have less direct control over. To make money, someone else has to pay you for something.