Not"continued high prices", but even HIGHER prices.
Which in itself, is not a bad thing. There is a biomass conversion available, that changes organic waste materials directly into petroleum. There is also extraction of petroleum from oil shale, coal gasification with reforming techniques, mining of Methane Hydrate from the ocean depths, and new-technology atomic power generation plants, which reclaim and re-use so-called "spent" fuel rods to continue producing energy.
The only thing standing in the way of widespread adoption of these fuel generation and recovery methods is the possibility that petroleum will FALL in price. Eventually this option has to be used up, as petroleum is bleeding out of the earth's strata at a lower rate than was perhaps the case 150 years ago, when the resources were first beginning to be tapped.
Petroleum is being constantly regenerated, you know. Part of the broad cycle of storing and releasing energy that has been going on since the dawn of time in the universe.