C++ Nano-Libraries and Package Managers

Especially in web development, package managers, like NPM and Bower, and nano-libraries, like chalk, are widespread. In my opinion, there's a good reason for that: You can integrate just what you need and it's well tested since a package only provides minimum functionality.

So why do we not use such a thing for other languages, like C++? There is Nuget, Conan and CPM, but they mostly contain big libraries, like OpenCV. What do you think about nano libraries in C++ and package managers? Do/Would you use them (if yes: which one and why?)? Would you contribute to an archive? What are the pros and cons?