To drill for oil and get half of what the going rate is would get you thrown off the company's BOD, or sued for fiduciary incompetence. The BOD of an oil company must try to make as much as they can for the company or resign. Conscience has nothing to do with capitalism. If XOM said they were going to cut their profits on purpose, there would be a stockholder revolt.
The only place gouging is possible, IMHO, is at the retail pump. The retail owner could decide to mark up 10 cents a gallon or $2.00 a gallon. All the rest of the system is a bidding situation. The refiner could mark it up if their weren't other refiners that would under cut him. It is bid on the Merc exchange also. I can buy unleaded gas for the same price the local station does if I want delivery.
Another myth is there is only 5 major oil companies. There are literally thousands. If XOM wanted to control the price, Murphy, Anadarko, Apache, etc, would have something to say about it, not to mention the foreign companies. The ignorance on this subject is embarrassing for a capitalist country.
ping - well put.