> there's no reason you shouldn't be paid the same for less time because your output is the same/better.
The reason is economic growth for the company / the country.
This in turn is a more subtle point than it seems at first glance. Not having economic growth isn't really a desirable option for a company, a country, or in (the long run) the people involved.
That was only true for a small period of time in America:
https://en.wikipedia.org/wiki/Great_Compression
Outside of that small 20ish year window, workers have never benefitted from increased productivity compared to the capitalists that have stolen $50 trillion from the masses:
https://time.com/5888024/50-trillion-income-inequality-ameri...