Alcohol has been in gasoline since at least the early 1990's. It's there to reduce emissions the way diesel has limits on sulfur to reduce harmful emissions.
To those that complain that alcohol is in gas, remember the days when dry gas (alcohol) was added in the winter?
This means that small engine manufacturers have had 30 years to figure how to make their equipment run well on gas/alcohol mix.
As to the price in diesel. I tried to google a chart on truck freight history that would point out what is common knowledge to know how diesel fuel demand has grown.
The change over from rail to truck has steadily grown from the 1920's.
Post WWII, the switch to diesel began. By the 1960's most 18 wheelers where diesel While many large straight trucks were still gas. In 1964 my local fire dept bought it's last gas powered fire trucks, two 1,000 gpm trucks.
By 1970's Diesels were replacing gas engines in large straight trucks.
I don't remember when school bus went diesel but their are no more diesel school buses whether full sized or mid sized.
1980's small and mid size trucks started to switch over to diesel.
Then since the 1990's the mall haulers, you know the 2,500 and 3,500 pickups whether SRW or DRW's, look like they are never used to carry anything but their wives shopping bags from the mall to their home have diesels in them.
Supply vs demand controls price. Not only have the number of trucks on the road have increased the number of gas powered trucks has decreased the diesel powered trucks have increased.