I am utterly confused by this statement. Are you implying that Bezos isn't one of the largest creators of wealth in the history of the world?
When I think of all the time and money hundreds of millions of people have saved by the revolution in online shopping and shipping, not to mention AWS, my mind boggles.
As you say, you can also generate wealth my extracting it (e.g., mining) but Amazon has not done that at all. The entirety of the wealth they've generated comes from increasing efficiency and productivity. That is, to go from trees and dyes to a book in my hand used to cost $Y and now costs $X. $Y - $X is the wealth created by the efficiency gains in those processes.
The fact that you can easily make vague pontifications about what else they might have done doesn't mean that any of those things are actually viable for the business.
> I know it’s hard to imagine that retail work could involve any amount of skill or knowledge, but this is no doubt a loss of value.
But probably not enough value to be worth keeping them on staff, unless they did the layoffs on whim, like you seem to think. It is possible that they examined a lot of scenarios and are privy to a fair amount of relevant details to which the public isn't.