They undergo intensive training for weeks before. Scripted, rehearsed, perfected, trained. I've witnessed it. There's not much space for natural expression in these talks. Everything is choreographed. Where to walk, look up, wave hand, smile etc all planned!
The stiffness is because the presenter is mainly a techie, developer or manager and not a natural performer. Their bodies are resisting the conformity by conforming to the letter but not the spirit.
Might be an attempt at Steve Jobs imitation with special focus on the worst aspects. Regardless of his reported reality distortion skills in person, I always found his big public presentations stiff and fake. I, as not-a-fan of game consoles, think that Mark Cerny gives fantastic presentations. He is always fluent, comfortable, and has an air of sincerity (while the contents are a little salesy). Kinda like a much more polished but slightly more fake John Carmack.
At least they didn't use 3d-generated hands holding fake phones this time. The uncanny valley in prior presentations was jarring when they'd go to a 3d "human hand"
