In part, gasoline is easily shipped and priced globally. They won’t sell it for $2 here when they can get $5 in Europe. Natural gas is not easily shipped and much cheaper since the shale boom.
The other parts are regulation, ethanol, taxes, shipping costs, and refinery capacity.
And crude oil. But that is only one of many factors.
as long as the bottom drops out of the LP gas market I’ll be happy.