Chevron Richmond refinery spent about 5 years to get a permit to upgrade the refinery. The cost was 1 billion and would allow the refinery to process heavier cheaper crude. After starting the project a suit was filed and stopped the project. The folks who filed the suit could not understand why Chevron laid off the 1200 folks working on the project.
If you can't even get approval to upgrade a refinery what chance do you think you would get to build a new one. There was also a refinery in Southern California that was shut down for economic reasons. It was purchased by Christian organization. They tried to restart the refinery but could not get the approvals so it was dismantled.
The final point is the integrated
oil companies make most of their money producing
oil not in refining and marketing products. In the 31 years I worked for one there were only a few years that the refining end made much money. Several years they actually lost money.