Your comment assumes free-market pricing, but crude oil exports from the USA used to be unlawful (the ban was lifted in 2015) and they could presumably become unlawful again. There is no legal reason why the US government could not extend such a ban to include refined petroleum.

https://www.pillsburylaw.com/en/news-and-insights/us-repeals...

Also, several oil-producing nations have off-market domestic pricing for refined petroleum that is favorable versus the international spot price. Such prices won't naturally change when, say, the Strait of Hormuz closes. The IMF has been trying to force free-market pricing, as was the cause of the Ecuador protests in 2019.