Second, npm was one of the first package managers to solve the classic "dependency hell" problem. In Python, if you have two dependencies, A and B, which both depend on different versions of C, say C@1.0.0 and C@2.0.0, respectively, then you're in trouble. You have an broken project. Python can only install one version of C. So now you're in dependency hell.
Npm on the other hand just installs both versions of C and it gives A the version that it wants, C@1.0.0. And it gives B the version that it wants, C@2.0.0. Both packages are happy - problem solved.
This caused Python maintainers to think twice before adding a new dependency lest they cause "dependency hell" for their users. Much better to just copy paste these 50 lines of code rather than adding a dependency. So there was an intrinsic sort of resistance – some pain is involved in adding new dependencies.
Npm maintainers had no such constraints. In a way, npm’s better developer experience led to the whole module ecosystem scaling "too well".
Disclosure: I started Socket (https://socket.dev) to help solve open source supply chain security. To learn more, see: https://news.ycombinator.com/item?id=30521913
Well, no, it's because the standard library is so good.