And I think both the original and my reply were about the demos themselves not about the mouse specifically or Apple in general. My point was that a technology demo of a research prototype and a product introduction are radically different things. I suspect that Engelbart's demo itself must have been a very early, (the first?) large-scale, live demonstration of interactive computer technology. They had to borrow an Eidophor from NASA to do it, which gives an idea of how unusual it was for the time. It's not like they showed up and plugged a coax cable into the projection system of the convention hall. That's one, among many reasons why one of these things is The Demo and the other a demo.

Teletypes had been commercially available for decades, and minicomputers (PDP-8) for about four years. It seems glass terminals started appearing only a year before this demo, though.

With this in mind, I will claim that the iPhone demonstration is similar in that it's the first case of a phone being connected to a big screen projector to demonstrate its functions live before a large audience.