Yeah downstream users wouldn't know that the license text came from someone who can actually license it. The combination of the copyright and permission notice

Yeah downstream users wouldn't know that the license text came from someone who can actually license it. The combination of the copyright and permission notice says "This is mine AND you can do these things with it if you want." Claiming ownership by itself does not result in it being open source. Saying you're giving permissions, but without claiming the right to be able to do so, also does not result in it being open source.