Much above $80 and shale oil becomes highly profitable. So swing producers like the US act as a soft ceiling.

That’s how it worked 10 years ago, that’s not really how it works now. The wildcat shale drillers of a decade ago all went bankrupt when prices fell, and lost a bunch of money for their investors. They’ve since all been bought up by larger firms with way more capital discipline, who don’t ramp up drilling just because prices have a little spike, especially when we all know that TACO. Do not expect shale drilling to soften the blow of oil price increases this time.