I think npm and ruby gems are quite a lot smaller than the average and upper bound size of docker images, which can easily be multiple GiB. Also the use case is

I think npm and ruby gems are quite a lot smaller than the average and upper bound size of docker images, which can easily be multiple GiB. Also the use case is different, where a docker build may incur a few manifest retrievals from the registry, while an npm build may incur hundreds. I don't know how quickly the average user would run into a 10000 download/hour limit for NPM, but if they were able to arrive at an equivalently high limit like 200/hr for docker, then maybe it would be fine to start charging for rate limits above that, and not impact most people.