Yes, it is a purposeful difference in philisophy. Python has challenges from the fact that its standard library is big - the interfaces (and so design) for a lot of these things are locked in place and you get stuck with suboptimal situations. And a lot of maintenance is required by the core team. Python 3 used the opportunity of backwards incompatibility to fix the worst issues, but that's a one time opportunity.
Rust consciously decided to keep the standard library minimal due to the backward compatibility guarantees they want to give, and then provide an excellent packaging story so that it's easy to pull in more capabilities. This allows for much faster iteration and improvement on what Python might consider 'core' capabilities.
Lots of the modules provided here are not the first attempt to achieve what they're doing. They're in the list because (the author considers them) the best. If they were in the standard library, maybe we'd be stuck with a worse version?
Rust consciously decided to keep the standard library minimal due to the backward compatibility guarantees they want to give, and then provide an excellent packaging story so that it's easy to pull in more capabilities. This allows for much faster iteration and improvement on what Python might consider 'core' capabilities.
Lots of the modules provided here are not the first attempt to achieve what they're doing. They're in the list because (the author considers them) the best. If they were in the standard library, maybe we'd be stuck with a worse version?