[ultraluminous]

"Obviously leaded gasoline actually did appear to be the better choice at that time, or else people would have just used the non-patent-encumbered ethanol."

Eh. "It could only be this way, because it was" is a textbook definition of begging the question and circular reasoning. It's entirely possible that there were multiple extrinsic reasons that lead to this situation that aren't "leaded fuel was just the better option". Marketing/PR, industry momentum, regulatory capture, cost-of-entry into the fuel industry. In fact it was noted below that the leaded fuel inventor has partnered with GM.

This is exactly what the GP meant by invoking History vs. Econ 101. You're assuming that this simplistic model of price/demand is an inevitable law of nature even though there are countless counter examples throughout history of the wrong decisions made for the wrong reasons.