Too bad the notion of completed/finished/done software is very weak. In theory, there it nothing wrong with an OSS project made by one person.
I would like to see the LOC these one-person projects with >1M downloads have. I suspect most of these are a simple Node/browser/OS API single-file wrappers that are simple to get right and treat it as complete.
At the same time such projects are easy to verify upon adding as dependency. Lately, I've just copy-pasted relevant parts of a library to my project because adding it as a dependency has a cost. I doubt this is a common practice though, especially in NPM land.
replies(2):