[ramin_hal9001]

I think you can beat the lone developer if the original developers take the time to thoroughly explain their code, at minimum in the comments, where it is good to point to papers explaining algorithms and techniques used. But also lots of example use cases explaining the various features of the code base -- not just "here is something cool you can do" examples, but "here is how these various functions can be used together, and this example shows how you can generalize to a larger problem." White papers can be useful for larger projects. There also needs to be some teaching work done: one-on-one conversations with colleagues for small projects, online videos presentations, and/or attending conferences for larger frameworks.

If you don't put effort into explaining your project to others, very few people will take the effort to learn it on their own, since the effort to understand your code might cost more in man-hours than the effort required to program everything from scratch.