Aliases turn a flat namespace into a potentially cyclical graph, and introduce all kinds of permission considerations (Should a non-owner be able to alias a project? If so, should they be allowed to update it?).
The solutions here are non-flat namespacing (which has worse UX, since `cargo install some-tool` now becomes `cargo install whats-their-handle-again/some-tool`) or some kind of content addressing (which is similarly bad for UX, if not worse). Most package indices choose neither, and "solve" the problem by playing whac-a-mole with abuse instead.
Clojars has the right idea for namespacing: some-tool is an alias for some-tool/some-tool.
This means the first package to squat on the name can use the shorthand version, while allowing other packages with the same name in other namespaces. (which may be forks or entirely different packages)
The solutions here are non-flat namespacing (which has worse UX, since `cargo install some-tool` now becomes `cargo install whats-their-handle-again/some-tool`) or some kind of content addressing (which is similarly bad for UX, if not worse). Most package indices choose neither, and "solve" the problem by playing whac-a-mole with abuse instead.