With 0 warehouse workers, the same is true. The bigger question is if Jeff Bezos were replaced with someone else, how much different would Amazon be? Unfortunately, we don't really have any tools to scientifically answer this type of question. My belief is that Amazon wouldn't be a thousand times smaller if Jeff Bezos were replace with another reasonably competent manager.

Also very important would be to ask how many of those 800k people would have similar or better payed jobs if Amazon didn't exist at all. Would there be an Amazon-shaped hole in the market, or would there actually be more economic activity if instead of one giant corporation there would be thousands of smaller ones? I believe the second is more likely to be true.