> the US concern outside of a major war, again, isn't who buys it but pumping and pricing policy
Of course it's about who buys (ie who can supply their economy with the energy it needs). The entire political value of oil is that it's critical to most economies. You keep saying that it's about controlling the oil, the point of that control is to use it for self-benefit. If the US were doing what you're claiming, it would be denying oil to China. You say that there is value in being able to deny oil supply to enemies - and then you pretend the US wouldn't have an interest in denying oil supply to China to slow its economic ascension (it obviously would benefit massively if it could partially suffocate China's growth via oil). These are contradictions in your theory, as China swims in Middle Eastern oil supply.
> though maintain any kind of optempo in a major war requires more than just adequate supplies for peacetime consumption, even after the inevitable rationing of non-militart use
Russian and Iranian oil production is drastically beyond their peacetime economic consumption. I can't imagine where you're trying to go with that.
> but even so they do have an interest in having supplies denied to an external enemy like, say, the US. Which motivates a desire to influence other exporters.
You're refuting yourself there. Then why didn't the US deny Chinese access to Iraqi oil? China almost immediately began benefiting immensely from Iraq's oil as production ramped up after the worst of the shutdown. Saudi's primary customer is now China and that is going to get a lot more dramatic in the coming decade. Those two points collapse what you're claiming.
If the US wanted to press an advantage, it would destroy Saudi Arabian and Iraqi oil supplies (use an ISIS-like mess), which would hammer China's economy by removing 1/4 to 1/3 of their oil supply. The US is now one of the few major nations that can fully support itself on energy. Instead, the US is actively protecting both Saudi and Iraq, while the largest US rival - China - benefits the most from that protection.