You should be comparing E85 to race gas, a full size intercooler, meth setup, not 91/93 gas. It's a MINIMUM of 105 octane and gets to be about 109 full blend but has the characteristics to be very competitive with C16 when used wisely. E85 can replace a full size intercooler but comes with some drawbacks and that is it needs a bigger fuel system, gas mileage is reduced. Anyone who is running E85 and overly concerned with gas mileage shouldn't be running it all the time.
Without the 10-20% ethanol blend in regular/some premium gas the price of that fuel would go up 40-60 cents. It's used as an octane adder which would normally be toluene, trimeth and a few others. The problem is that those additives are very expensive, ethanol is less.
The main problem with ethanol is the misinformation.