I don't believe all the hyped-up "green" nonsense about electric & hybrid cars for exactly the same reason. When looking at whether something is really "green" you have to consider how much resources went into making it, and divide that by how many years service you manage to get out of it. One of my motors is almost 59 years old, and still has all of it's original mechanical units, so I won't be taking any lectures from pious tree-huggers about how "green" their new car full of toxic batteries is, until such time as it outlasts mine. Most modern non-electric push bikes are not going to survive anywhere near as long as old school ones have either. It's a throwaway world today and there's nothing "green" about it!