I follow the development of a header-only C++ library that I use and, besides a small community of users who help the author test and report bugs, its just one

I follow the development of a header-only C++ library that I use and, besides a small community of users who help the author test and report bugs, its just one guy and the amount of features he's implemented in the past few months, due to him or members of the community needing the feature, is quite substantial. Its always wonderful to see substantial features or optimisations implemented shortly after seeing a discussion on it. The velocity of some of these projects is incredible. Its not necessarily just "small teams move faster". It can be, but also it depends on the passion and energy of the individuals.