The author seems to be suggesting that one can "finish" a project solely by limiting technical scope. But what really allows one to finish is limiting the set of users and use cases. Limiting technical scope is just an indirect way of accomplishing this.

So there's a huge tradeoff between "finishing" and potential impact. I've heard of ZeroMQ. Until today I'd never heard of Libmill.

And that's okay! I'm just saying I don't think it's possible to have a project that both has a large set of users and covers a narrow enough set of functionality that it can be "finished" by a single person.