I am, by no means, not an expert on why energy is so costly. I do, however, have some thoughts on why.
First, usually at this time of year some refinery capacity is off line for maintenance. Right now there is four times the normal capacity off line, further reducing the available gasoline at a time when gas demand rises. High demand - limited supply equals higher prices. There have been no new refineries build in the US since the 1970's. Have there been proposals...yes. The ecology folks rise up to oppose, the local citizens don't want a refinery in their back yard. I suspect that it would be a costly fight to get approval. My opinion on this is partially shaped on the current pissing contest going on over the proposal to expand the natural gas terminal on the Taunton River between Fall River and Somerset, Massachusetts. One of these years, we will have a harsh winter and the same folks will want to know why they may not have sufficient supplies to keep warm. This past winter there was a delay in getting a propane tankers into the Providence port. Some rural folks were affected, and some ran out.
I certainly have no answers. I do know that I will pay the piper for the gas I need.