> With that background in mind it answers the obvious question
> of... why did the presenter show Unity through screenshots
> rather than a live demonstration of it?
1) I really don't like giving live demos of software. I find it hard to keep them compelling for audiences because you spend a lot of time moving around in the software which results in dead time.
2) I wanted to switch to demo Unity during the questions because many of them would have been helped significantly with a demo. But, I could only get the projection system to recognize at 640x480. Which was fine for slides, but wouldn't have worked for demoing Unity.