True, but at least in America bikes alone are not a great option.
Over 60 million (1 in 5) Americans live in rural areas. These places don't have public transportation or are so spread out that bikes are not practical.
My 4-person household has one car, one electric cargo bike with two kid seats, a regular bicycle, accounts with bikeshare/scooter options around our city, plus mass transit passes, plus the option of Uber/Lyft.
Bikes might not work as a replacement for a first car, but they can work pretty well as a replacement for a second car, and a tool for reducing total mileage on the car you own.
Everything depends on where you live, of course, but a substantial number of people live in a place where a bike can reduce the number of miles you drive, even if you never actually give up the car.