Assume Rubygems chose to operate in that way, where all gems must be owned by a group rather than an individual user.
Then, assume that the most flexible option is for each gem to be owned by a unique group: that way even if two gems are maintained by the same users right now, they use two distinct groups in case that ownership changes in the future.
We might as well just name the “group” the same as the gem name, since only one gem is managed by each group. So now the “purescript” group maintains “purescript”, the “pry” group maintains “pry”, etc.
As syntactic sugar for users, since the group name and gem name will always match, why make them type both? Let’s have all the commands support just referencing the gem name. If somebody wants to fork a gem and release it, their group and gem get a new name.
I think there’s a pretty compelling case that package managers should support group ACLing on publishing (giving multiple humans the first-class right to publish using individual creds to a group namespace, with the ability to add/remove users from the group over time. But once you’ve done that, the distinction between explicit group-name-in-package-path and changing-name-to-fork (so the difference between fork-group/orig-name and orig-name_fork-group) seems to shrink.