Interesting perspective on long-term projects. I too am working on a service I consider my forever project, but one which may actually be launchable quite soon. I can definitely relate to the dreamy state the author refers to, as I too dream of a constant barrage of features I want to build into the service. This can quickly get out of control though and become endless as a developer delves deeper, but maybe that's why it's a forever project. You want this service to exist so bad for yourself, it doesn't matter if you're the only user. It's sort of like a nagging child. It's a part of you, no matter how many diapers you got to change.
I think that part of what the author is trying to convey about such projects, rather than they being de facto 'forever projects' is that such projects are worth it by the journey alone. Even if you don't ever reach the end of it - the inspiration and learnings it gives you is enough to motivate continue working on it.