But the problem is that the product is buggy. The question then is "can you fix those bugs before products ship."

I'm not sure what the problem is here. Customers don't want buggy products. Live demos are more informative to users who can't tell what the actual experience will be like vs what the envisioned experience is.

I'm sorry, but as a customer I don't care what's in a developer's dreams, I care what I can buy.