According to Wikipedia there were a total of 63 million automobiles made in 2005. That works out to two per second every second for the whole year.
In my Computer Architecture class we’re about to discuss pipelining and the professor used the analogy of car assembly lines. He asked if anyone could guess how long it takes to make a single car. It takes approximately a couple of days for a single car to move from beginning of the line to the end, but when you recognize that some large number of cars are being assembled in a single plant, and there are so many plants, it breaks down to where each car, were it made by hand, would be produced in a very minuscule time period.
I still say we should switch to entirely electric cars. In ten or fifty years, whenever we finally switch off of petroleum, we will have a ton of vehicles that won’t run on hydrogen or banana peels. If we then run out of banana peels or pondscum we’ll have to build new cars to replace those.
With electric cars, you have a energy-source-agnostic vehicle. You can switch electricity production to clams or lightning or whatever might be reasonable, efficient, and safe at the time.
It’s the difference between building a language like java or a video player that has its codecs installed as modules or plugins and a monolithic and architecture specific system. Both will work, and to a small extent the monolith will be more efficient in the short term. In the long term it’s a nightmare to maintain and ends up costing you more.