Well, in 3 to 5 years, when this thing is finally released, I'm sure people will believe them, though the whole tech will be less impressuve by then as all the other techs will not stand still during this time.
I think he makes a fine point in his critic of polygon graphics... It is old tech everyone still clings to because developing something new costs loads of time and money (and noone wants to spend those if they can get around it).
What he fails to see though is the typical thing you have with "specialists": some of the newer examples of polygonal graphics he shows in the video (is it the new carmack title?) are, thanks to bump mapping, looking really nice. How many people will even notice that this actually is low poly graphics? How many of these will care?
He certainly struck the wrong chord in the first video, as poly graphics, as it is today, is more than good enough for 99% of gamers.
Its a different aspect he only mentions in a second interview video, that made this whole thing interesting to me: that the scenes he showed was all rendered by software on the CPU. If true, that means you could get much better graphics at 60 FPS stable out of a low power notebook. Thats really impressive... If its true, and they deliver more than just videos before I die of old age