I think that's a very appropriate (if oblique) 'car analogy'. To extend it further, one might consider an alternative to the ubiquitous IC, the steam engine: e

I think that's a very appropriate (if oblique) 'car analogy'. To extend it further, one might consider an alternative to the ubiquitous IC, the steam engine: external combustion, clean(er), more efficient, multi-fuel... Aside: steam cars were actively developed throughout the 20th century, even advancing to a sports car in the 1960s. The best article I read on this subject was 'Steamer Time?' by Wallace West, in the September 1968 issue of Analog Science Fiction. Fittingly, the same article mentions the concept of 'steam engine time', a term coined by Charles Fort, who "contended that the steamboat was invented only when economic, political, scientific and engineering developments combined to usher in steamboat time."