Why don't people invest more? Chinese peasants traditionally saved 50% of their income until consumerism took over in recent years,
Why don't people fix their own stuff (or pay more for higher quality that lasts longer)? Changing brake pads, various filters and fluids or oil on a car is not hard and requires less than a $100 investment in tools, even on cars with all sorts of fancy computers and sensors. Same is true for plumbing and electrical repairs on a house.
Why do people pay for cable, cell phone packages, large trucks and other stuff they don't need?
The average american home has increased more than 25% since the 50's. People have more cars and toys and eat out far more often than they did back then.
If you went back to a 1950's like lifestyle but on a 2015 income, you would be able to save a lot more money via frugality.