It's just higher cost for no gain. In fact, premium gas can actually be a tad lower in energy content than regular. In an engine with the compression ratio that can take advantage of the higher octane more energy form the fuel can be converted to propulsion because of the longer power stroke.
GM's 1.4L turbo was designed for the higher octane available in Europe. They just advertise it as regular fuel here. All modern engines have knock sensors, and very few actually need premium. Some sport super cars are probably the only ones. The premium where the the company is likely higher octane than our premium here.
I've tried higher octane in the Sonic, and it does get better fuel economy. Just not enough to be cost effective with the current price differences. It might be if I mix the premium and regular for midgrade myself.
Little fact. Not only is the test fuel the EPA uses ethanol free, but it is also 93 octane. If you have a turbo, DI, or an engine that seems to have a higher compression ratio than needed, and are wondering why you aren't getting the EPA rating. Too low of an octane fuel could be part of the reason.
An example of why our fuel ethanol program is half assed is in the design of available flex fuel engines. Ethanol has an effective octane of 105. That means E85 is well above regular and around premium in octane. Flex fuel engines are based on low compression, low octane engines though. The fuel economy loss of E85 would be mitigated some, and performance increased by using a higher compression.
If the higher octane is standardized, is there any actual reason regular would be priced higher than now? After all, crude prices aside, the inflation-adjusted price for gasoline hasn't changed much even as the octane ratings have climbed.
Since regular won't be going up to premium levels, I don't see the price increasing much. Some of the compounds used to raise octane are valuable products in their own right though. The refineries might just increase the ethanol content.
We are getting ultra low sulfur gasoline phased in this year for Tier 3 emissions rules.
Oxygenates in gas needs to also be revisited. They do help reduce emissions in carbureted engines, but no such engine is being put into cars on sale now, and the numbers of those on the roads is shrinking.