Isn't that one of the big justifications for not bundling the standard library?

It seems to me like not shipping the std library with the runtime is potentially one of the biggest language innovations we've seen in awhile because it should allow the std library to evolve over time in a much more graceful way ... -- you'll actually be able to make breaking changes to the std library as folks who are unwilling to update their code can just use the older version (until the ossified code becomes irrelevant which eventually code that is never changed eventually will)

Python packages, in general, are much bigger though.

And you'd probably be surprised how much the stdlib is used. In many environments third party libraries have to be vetted by security, or the developers are junior and can't probably check/understand a third party library so they just take the safe option and use the stdlib and hand-code a bit to make it do what they want, etc.

Plus, the third party packages that are used generally have to offer much higher convenience or quality or scope (or all three) to be adopted over the stdlib alternative.

So the bar is much higher than leftpad or is-odd.

Not really, I mean what do you think is missing from the standard library json package? It obviously solves most use cases since just yesterday flask dropped simplejson. Standard library is just not great for libraries that are not yet stable.