There are many such examples for npm as well: many "compatible" managers, one registry.
Sorry, examples of what? Package managers that present themselves as replacements for other package managers? Or package managers that aren't compatible with the registry they're supposed to be compatible with? Your use of scare quotes is confusing.
Sorry, examples of what? Package managers that present themselves as replacements for other package managers? Or package managers that aren't compatible with the registry they're supposed to be compatible with? Your use of scare quotes is confusing.