Modern wars aren't fought out of rational calculation that they'll improve the situation. They're fought when existing conflicts have their flames fanned just a bit too much, or when factors holding them in check suddenly change. I think the smart money is that oil prices will recover soon - but if they don't, we'll discover a whole world of conflicts which were previously suppressed by the reliable invariant of a rich Saudi government.

Broke governments can't subsidize food, water, medical care, or other services. The Arab Spring was kicked off by a local drought and rising food prices. It's easy to support a repressive monarchy when the money is flowing and you're sittin pretty while well fed, and in comfy AC.

Example: https://www.theguardian.com/lifeandstyle/2011/jul/17/bread-f...

The Arab Spring in Syria led to rebellions that spilled into Turkey and Iraq (Kurds, ISIS, Russian and US intervention, etc.).

> Even if you capture someone else's oilfields...then what? Produce oil there at a loss too?

They're not after oil fields per se, but changes in control, money, and other resources. If oil is so cheap that the price is negative then it means you can fly your attack craft without worrying about fuel costs...