Whenever I try to think about these large scale systems I end up realizing how difficult it is to predict the outcome. Everything people are buying has to be produced. Everything produced needs people (or automation) producing it. Somewhere there is an equilibrium.
What's happening globally has an impact (e.g. we possibly had a better standard of living by taking advantage of places that had a lower standard of living). Competition (and inequality) has an impact because not getting ahead of the game can put you in the bottom rungs where you're really doing badly. In a game where only the top 20% are doing well there is fierce never ending competition to be in that 20%. In a game where everyone has some guaranteed basic standard of living you would expect the competition to be less fierce.
Another note is that people used to work crazy hours during the industrial revolution. Similar story there, you had to get some work if you didn't want to be poor, and it was easy for employers to take advantage of employees.