Which is silly, considering good automatics are better than a human in terms of shifting.
Why can't automakers put out a supercar with a 1.6L 4 banger? The vast majority of people don't need to go faster than 80PMH. Give them something that looks good. A car that looked like a Ferrari and performed like a Civic for the price of a Hyundai would sell through in hours.
It's not silly if you consider more than the single semi-true factoid you just mentioned. A vast majority of people interested in sports cars prefer to shift manually, why design an AT for the very small market share that wants it?
I think the mythical "most people" being cited by numerous posters in this thread really should be "car nuts like me."
The simple fact of the matter is that our current car selection is due to mostly market demand, a bit of crash safety and other regulations, and a dash of lawyer-ing.
Why don't we see mid-engined cars anymore? Your average driver will tend to spin a mid-engine car, likely resulting in a lawsuit. Requires a whole new vehicle platform to be developed for a small market segment. It is difficult to pass modern crash safety requirements with an engine behind the driver instead of in front. Pick one.
Why isn't there a small diesel truck yet? Fuel is still relatively cheap here. Large trucks command large profits. Diesel engines have had a rough time passing emissions in the US lately.
Why don't we see diesel hybrids? Price point, do you really think people are willing to pay a premium for a diesel engine and then another premium for a hybrid driveline? See above for issues getting diesel engines legal in the US.
Why don't we see high-powered RWD coupes with few or no options? No one outside of a few thousand (hundred?) track nuts would ever want one AND have the disposable income to buy a brand-new car whose only utility is track driving. It would still be porky and complicated compared to old cars given modern crash safety and emissions regulations.
Why don't we see high-powered BRZ-type cars? Too much power, too easy to wreck the car without further investment in ESC systems (see interviews with BRZ/FRS designer). Also price-point. All that power comes at the cost of cash, weight, and reliability. Then it's competing with the Mustang, 370Z, etc instead of filling it's own niche.
Why no turbine cars? Idling efficiency.
Why no ultra-light modestly powered kit-car-like cars? Crash safety regulations.