For example, consider single mothers working two jobs, ordering from Amazon.com to save time & money. And depending on where they live, they might even get the order within a couple hours. That's a new kind of efficiency that many benefit from.

Low prices aren't free. Some of it came from efficiency, the rest comes from simply paying labor less.

https://www.bls.gov/opub/ted/2018/4-point-9-percent-of-worke...

That's not to say it's casual. Maybe it would've decreased more sans Amazon. Who knows.

Anyway, the point was simply that it's not only/mostly engineers who derive value from their existence. It includes every Amazon customer who saves time & money - especially those who have too little of both.

For tens of millions of working poor who live in apartment complexes, Amazon provides absolutely zero benefit since they cannot order anything bigger than a kumquat without risk of it being stolen off of their porch. The office? The office doesnt exist or is closed during the hours they are working - and UPS wont deliver there anyways a lot of the time.