Requests depends on urllib3 which would also have to go into the stdlib. It also contains a CA bundle which the core devs don’t want to do. It also likely the internal implementation doesn’t follow core dev standards and practices, a common problem with integrating external libs. Finally there’s a risk it would slow or discourage new feature development by tying it to the core release cycle.

A better approach might be to add a core of basic requests-like features built from the stdlib’s existing resources. That would be beneficial to many users and if they need more then there’s always Requests.