system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The last time gas was this price, higher grade gas was $0.10 more and premium was another $0.10. Right now it's $0.30 more for each upgrade. What changed?

Just to clarify, people, I'm not asking for the difference between the grades of gasoline, or why premium costs more than simple unleaded.

My question is why the markup itself on higher-octane fuels has increased so significantly, 3x what it was.

Yes, rich people are willing to pay more, but what changed that the rich are willing to pay *even more* than they used to.  Or is it a supply problem?  Something else?
gpt
Nothing, the owners know that they can get away with putting a bigger markup on premium so they do. People that get premium are not as discerning when it comes to price. Also many gas stations only have the price of regular displayed so you really can not tell the price of premium until you get to the pump. Lastly compared to Europe, we do not have that many vehicles that require a higher octane gasoline so people really don't get that much up in arms about it.  Source: our company builds and leases out gas stations and also we run c-store distribution company.