Who benefited from Ford making cars more efficiently ? Their employees as well, since they could buy cars on their own at cheaper prices than the then available cars.
Productivity gains improve life for EVERYONE, even the poorer ones. There's so many examples I don't even know what kind of point you are trying to make here.
Improvements in agriculture make food cheaper as well, which makes it possible for even modest household to have 3 smartphones on top of food of the table, and go on vacation more than 0 times a year.
Sometimes when I read comments here, I get the bizarre impression that nobody has noticed the massive increase of purchasing power that society got in the past 100 years. I must be living in a bubble.