Price of energy too low for producers, too high for consumers. The gap has been filled by debt. But debt is a bet on future profits, but there is no more cheap energy, so there won't be any future profits.
Our problem is not just that oil prices that are too low. Prices are too low for practically every type of energy producer, and in many parts of the globe.https://ourfiniteworld.com/2019/09/12/our-energy-and-debt-predicament-in-2019/
The world economy seems to be running out of truly productive uses for debt. There are investments available, but the rate of return is very low. The lack of investments with adequate return is a significant part of what is preventing the economy from being able to support higher interest rates.