How much did a bike cost in 1920? Probably a worker's monthly wages or more and that was a heavy single speed bike. For a monthly wage, even at minimum wage, you can buy a decent commuter bike nowadays.
People say they want a simple bike, then buy the colorful full suspension bike at Walmart. Walmart sells exactly what people actually buy. If people buy a decent rigid commuter bike for $500, Walmart would sell it. But people only talk about buying a decent bike, then end up with the cheap one.
The terrible truth is, to buy a decent bike people would have to give up smoking, drinking, drugs and Starbucks. And that actually tells us people's priorities.
It is not different with cars. Many years ago I worked at Starbucks. People came every day to buy a $5 coffee. But didn't have money to fix their driver side mirror that had fallen off. 1 month brewing coffee at home would have paid for a life saving safety feature. Priorities....