> But was the entire supply in the rest of the world completely without any slack? Everything was running at capacity, with zero capacity to increase deliveries?

I'm trying to find some numbers here and failing utterly (thanks AI for utterly ruining search). But my recollection from when I've seen it discussed in the past is that the vast majority of slack oil production is in the OPEC countries--essentially everybody not in OPEC produces every drop they can--and even of that, the really big source of slack is Saudi Arabia. You know, all of the places that are currently unable to ship any oil because of the closure of the Strait of Hormuz.