Fuel grade and the market?

Will there be an effect on a car's designed fuel grade and consumer preference in the marketplace?
By that, I mean that currently, designing an engine for the highest octane allowed (by a scenario, by a contest, by the game, whatever), even if it's higher than what would be considered "normal", is essentially just giving away free RON/AKI to the builder to play. From what I've seen of Der Bayer's contest calculations as far as fuel cost to the buyer, it makes a minimal difference, and likely two otherwise identical cars with only different tuning for regular and premium fuel would easily go to the premium fuel model in the simulations. (correct me if I'm wrong, of course)
Now, maybe Europe's market is different, since you have mandated higher grade fuels, but that is totally not the way it works in the US. People don't like paying for premium if they don't have to. Cars that REQUIRE premium gas are generally high performance and/or luxury models (Mercedes, WRX or Evo, etc.). Only a couple "regular" passenger cars have to use fuel, such as the turbo version of the new Dodge Dart (and I bet you $$ that a good chunk of buyers aren't aware of this and are going to knock their engines to death on 87 AKI).
Will the market, at least for areas/times that do NOT have required use of high-grade fuels reflect this preference?
By that, I mean that currently, designing an engine for the highest octane allowed (by a scenario, by a contest, by the game, whatever), even if it's higher than what would be considered "normal", is essentially just giving away free RON/AKI to the builder to play. From what I've seen of Der Bayer's contest calculations as far as fuel cost to the buyer, it makes a minimal difference, and likely two otherwise identical cars with only different tuning for regular and premium fuel would easily go to the premium fuel model in the simulations. (correct me if I'm wrong, of course)
Now, maybe Europe's market is different, since you have mandated higher grade fuels, but that is totally not the way it works in the US. People don't like paying for premium if they don't have to. Cars that REQUIRE premium gas are generally high performance and/or luxury models (Mercedes, WRX or Evo, etc.). Only a couple "regular" passenger cars have to use fuel, such as the turbo version of the new Dodge Dart (and I bet you $$ that a good chunk of buyers aren't aware of this and are going to knock their engines to death on 87 AKI).
Will the market, at least for areas/times that do NOT have required use of high-grade fuels reflect this preference?