Especially since one of the bugs I'm likely to fix is, "why is this library so damned big?"
Artifact size depends on what garbage from the project infrastructure gets included into the artifact. So simple things like not having a fully populated ignore file will cause things to get included into the project or the artifact.
People who don't care about file size don't care about file size. If the artifact is ridiculous, sometimes the repo is ridiculous too. Therefore if you take a bunch of projects with outsized artifacts, you are going to have above average repository sizes as well.
Because it sounds like you want to use 100% of the service and not pay for it.
In a way I'm almost glad people will have to start cleaning up after themselves.