The US can produce more than anyone else. But they can't produce enough of the correct type of crude. What they can produce is good for gasoline, but not other fuel types without investing heavily in refactoring infrastructure which would take years. It's cheaper to just buy it from others. That's why diesel is skyrocketing. This is what they quickly discovered after kidnapping Venezuela's leader. US imports most of their heavy oil from Canada, who he has spent months destroying relationships and agreements with because they refuse to bend the knee.

He just enacted an emergency order for California to re-open sites off the coast. It won't be enough. US would still need to import millions of barrels a day to keep inflation down.

Simple answer: Money. Because businesses would rather sell it for market price on the global market than for cheap to domestic customers.

Domestic production was one of the perks of North Sea oil exploration that was sold to the British public, but it never led to lowered gas or electricity bills...

My guess is a combination of restricted supply and speculation. The largely unregulated market of the u.s. is allows investors to just buy up the supply of a commodity especially if everyone knows the price is about to jump. Add to that the fact that a large % of the world's oil passes through the straight of hormuz means that a lot of gas that would be used in the states is being shipped elsewhere.

The US doesn't produce all of the oil they need.

And all of oil has the same price (taking into account its composition, transportation costs, etc), so it doesn't happen that 70% of the fuel you buy is cheaper, and only the last 30% gets more expensive. The oil producers are always happy to cash-in the difference and sell it at the market price.