I think this comment shows the difference between web development and other industries.
This problem is not existent in languages that traditionally use single-file libraries because projects rarely get to the point where they use 63 libraries, let alone have 63 indirect dependencies to a library.
Also: popular single-file libraries in the tradition of stb won't even have dependencies to other libraries of the sort, only to the standard library.
If your dependency graph is simple enough that you don't have any indirect dependencies, then it really doesn't matter what you use for dependency management.
Modern dependency management tools are designed for more complicated cases.
If the goal of your dependency system is to reduce the number of dependencies that library authors include, isn't encouraging people to make single-file libraries counterproductive?
This problem is not existent in languages that traditionally use single-file libraries because projects rarely get to the point where they use 63 libraries, let alone have 63 indirect dependencies to a library.
Also: popular single-file libraries in the tradition of stb won't even have dependencies to other libraries of the sort, only to the standard library.