I don't think Peak Oil ever really went away. Those who state with some satisfaction that tight oil extraction has somehow "beaten" peak oil have inadvertently been dancing to peak oil's music IMO.so peak oil could be on it's way back.
People like Richard Heinberg and John Michael Greer have been predicting this "tumbling down a staircase" style of collapse in which we have a period of high oil price, allowing unconventional production, leading to tough economic conditions, leading to demand-destruction, leading to a price-collapse, leading to shortages as some sources become non-viable, leading to a spike in prices.
Meanwhile the World continues to consume the oil, meaning that next time demand is high, a greater percentage of demand will need to be met from unconventional sources, requiring an even higher price. All this against a background of increasingly unsustainable debt.
The final arbiter is EROEI. As this continues to fall, we will have to adapt to a lower energy economy, either by transition or collapse. I don't see too much of the transition going on at the moment.
I wonder if anyone has actually asked the question; all this debt that the shale industry has accrued - how are they going to pay it back now that we have entered a regime of lower prices?