You can't "jawbone" your way to lower prices on anything. Thats embarrassing. You lower prices by drilling and building refineries.
If there isn't enough competition to make that happen, then that is where you intervene, to increase competition. The US government stood by and watched the majors merge and merge again during the nineties, and fewer players in any market is not in the consumer's interest.
But present policy is to allow mergers, and make the construction of any kind of energy facility exceedingly difficult. Tenured professors may think thats a great idea, but if you work for a living, or aspire to, its not good news.
I am glad you brought up how mergers have reduced competative pricing in this industry.