As one who has worked in the "oil patch" for 25 years, I feel that 'Boom Town' is the most realistic portrait of the industry (during that period) that has ever been put on film. The formation of the cartel mimics the origins of Standard Oil. Also, the 'feel' of the picture is right and the industry is not romanticized as in other films. Perhaps, as was noted in other comments, this is because of Gable's experience as a wildcatter.
Several others have noted, or objected to, Gable's speech about the nature of the industry. Yes, it is decidedly pro-business and anti-government, but it is not really laissez faire. The film argues for controlled production of oil fields to maximize their long-term benefit. This speech is amazingly prescient of our current crisis.
I watch this one every time it airs.
