Of course we have a number of packages that are truly trivial and should probably be inlined. Npm is a completely open platform. Anyone can upload any module they feel like. That doesn't mean anyone else will feel the need to use them.
I think you'll find that the vast majority of small modules that are widely used are ones that also cover obscure corner cases and do benefit from widespread use and testing.
You don't have to be widely used to be widely used, though. I bet there are tons of developers who would never dream of using left-pad or is-positive-integer, but nevertheless have copies of them (multiple copies?) on their computers due to transitive dependencies.
Of course we have a number of packages that are truly trivial and should probably be inlined. Npm is a completely open platform. Anyone can upload any module they feel like. That doesn't mean anyone else will feel the need to use them.
I think you'll find that the vast majority of small modules that are widely used are ones that also cover obscure corner cases and do benefit from widespread use and testing.