I can say, as a SysAdmin, I have been taught and tell my users to check the domain to verify a website is real.

It's a strange edgecase that the owner of John.Doe.com does not need to own Doe.com

In every other case that I know about, to own the Joe subdomain of Doe.com, you would need to own Doe.com

edit: I guess I've gotten so used to the government 3LDs I just don't even see them anymore, or just see something like .co.uk or .edu.us as a TLD by itself, but yeah those exist too. Still the exception to the rule

True, they can’t outright prevent the ambiguity, but much fewer people will go to the trouble of establishing such subdomains when the option isn’t directly offered by the registrar.

This is my theory because, a priori, 3LDs should be more profitable than 2LDs, because with 3LDs John Doe and Jane Doe don’t have to compete over doe.name, but instead can each separately purchase john.doe.name and jane.doe.name. Apparently, however, that’s not a benefit of 3LDs in practice, which leads me to conclude that john-doe.name and jane-doe.name just sell better.