This is how registries have worked since their inception (afaik). And yes, it's a monopoly. ICANN designates what TLDs are valid Registries own individual

This is how registries have worked since their inception (afaik). And yes, it's a monopoly. ICANN designates what TLDs are valid Registries own individual TLDs fully Registrars resell domains on those TLDs that registries own.