Part of why you feel that way I assume is because of how where you live is set up, it probably is unfathomable to operate a family without a car, and you shouldn't be worried about that changing any time soon. But proponents for bike infrastructure are not suggesting you put your kids in a bike trailer and ride 40 miles to school, and they aren't suggesting we remove the highways taking you from suburbia into the city. They are usually suggesting that we need more bike or walk friendly neighborhoods. But we also can't all live in the city, so bike friendly infrastructure is also necessary between suburbia and the necessities like work and shopping.