Heres what I seen, pertaining to the lack of heat.
In the beginning of the video, like sidney pointed out, the bottom vents are closed.
At 8:28 We can see the OT blade covering the vent under the lit charcoal. That makes a 100$ difference.
Then at 8:50-8:52 he cooks food and we all can clearly see the vent handle in the closed position.
At 12:18 when the review is wrapping down the bottom vent is finally open and the weber is all fired up and smoking like it should have been the whole time.