It is extremely likely it will cost even more, soon – if only because of the decreased purchasing power of the "money" we're forced to use to buy it with. That "money" being nothing more substantial than an officially endorsed piece of paper, of which many more can be printed at will by those who officiate – who control the printing presses, causing those previously printed to be worth less.
People used to talk about watching a "gas guzzler's" fuel gauge needle go down as you drove. How about a gauge for the buying power of money? How fast does the government "guzzle" that?
But it's not just that money buys less gas. There is also less gas.
And diesel, too – which can be thought of as less-refined oil, out of which both gas and diesel are made. Oil is being rendered artificially scarce – via restrictions on its extraction and "regulations" (an official sounding word meant to make decrees sound legitimate) that make it expensive to refine and taxes that make it expensive to buy – in order to counter the great abundance of this beneficent substance.
By rendering it artificially expensive.
For the same reason that it is artificially expensive to legally own a rifle capable of automatic fire, which isn't a type of weapon that naturally costs three or four times as much to make as a semi-auto rife of similar type. It just costs more – because the government doesn't want you to own one.