Let's compromise:
For maximum performance the best octane is 91 or higher. One can get an extra 2% hp at the crank under hard acceleration which equates to nothing measurable as far as time on a 0-60 run.
For maximum pocketbook impact, the best octane is regular (87 octane at sea level) for a 20% savings to the pocketbook.
If 87 Octane isn't enough to prevent knock, the ECU immediately detect it and will retard timing to eliminate the knock and the car will continue running as designed. The owner will maintain their factory warranty and everybody is happy. Those that absolutely need that extra approximately 7 hp can feed their power addiction and those that don't can have more beer money.
As for me an my house, we will have both: maximum hp/tq through my tune + premium fuel and as much beer as I like because I can.