QUALITY of life is important. You can save the planet, but we might all end up living like termites. Education is the only factor which has ever slowed the rate of global population growth. Education brings wealth which reduces the need for large families to provide a form of superannuation for the ageing population. As far as commuter vehicles are concerned, we could all ride and race 125cc single cylinder four-strokes. The trouble is that most people cannot even drive a car properly, let alone a motorcycle.
There was a friend of mine who used to ride a Yamaha pedallie from Ivanhoe to South Melbourne every day. When he was on the road, he used the little motor, while on the cycle path, he pedalled. You don't really need to drag a ton and a half of steel with you, everywhere you go.