2016 was the fallout from the shale oil boom. 

That's no doubt. And it really didn't have much to do with Obama's policies. It was supply and demand. 

Trump asked OPEC to increase production to "lower gas prices" in, I think, 2017, and, they did. That led to the surge of bankruptcies in 2018, 2019, and the first quarter of 2020 before Covid. You can directly link it back to Trumps actions. Then they approved the sale of the largest refinery system in the U.S. to - Aramco. And, yes, second and third quarters of 2020 were brutal for the oil and gas industry. OPEC cut production, and, once again, because of a Trump agreement, wouldn't increase production until months after demand ramped back up, causing the higher gas prices at the beginning of the Biden administration. The U.S. oil industry was slow to ramp up because the smaller, nimble players were gone, and the large players wanted to insure returns.

It's not that complicated.