Most drivers are morons. That is 100% correct. How good for the environment is a Chevy Volt or Tesla when 75% of the electricity in the USA is generated by burning coal.
As for the |Hummer vs Prius, the key is that the Hummer is really just a GMC 1500 pickup with different body work (and 15k added to the price tag). So, evey full sixed GM pickup and SUV shares 90+% of the parts, hose basic design is unchanged for 5-10 years at a time. So when one Hummer dies, the parts end up in the junkyard and can be use on ANY full sized pickup or SUV.