Where are you filling up? I have never seen .75-1.00/gal difference that I can remember... I’m filling up at Costco now, .30-.35/gal difference, so ~$7/gal per fillup. Yes, other places are 0.40-0.50/gal more.
On a different note, folks can think & do/run whatever they want, but this motor needs premium to run to it’s published specs, etc. Can programming, knock sensors, etc, compensate? Yes, but you won’t get the same performance. If driven mildly yes you may get the same mileage, but not when you push/work it. Ford’s ecoboost is the same - manual says run a minimum of 87 but the goes on to say for best performance and to meet published specs to run premium. More and more vehicle are going towards premium due to CAFE and emissions standards.
There is a push to have all new vehicles run premium (or even higher octane than current premium) - engines designed to run premium get better gas mileage, and thats why it’s being discussed (by manufacturers, fuels producers, .gov, etc).