Lower oil price forces tax regime changes
Most oil producers on earth live off the proceeds oil gives them. As the bounty has been good for many decades, many of them never learned any useful skills. Hell, they even discouraged them as this requires entrepreneurial people and those kind of people are hard to handle. What less than free regime wants lots of free thinking, rationalizing people that are used to take things in their own hands? So people were coddled with lots of cash. But what happens when oil cash does not suffice anymore? The world has a new biggest oil producer now and this oil producer does not need the proceeds from oil sales. It likes low prices as this is good fertilizer for economic activity in the US. There is no remedy for this dynamic. Oil producers either adapt or go away.
The effective oil price ceiling created by the US shale boom is causing governments elsewhere to revise their tax codes