My understanding is that it was hydraulic fracking that made the difference.
See, the 'peak oil' people were wrong; turns out that if you are willing to pay more, there's a lot more oil you can extract (albeit at a higher cost)
I actually think it was a self-defeating prophecy in a way. The peak oil folks actually had some mindshare for a while, and there was a lot of investment in more expensive ways to get oil out of the ground that had the assumption of long term oil prices being over a hundred bucks a barrel. This, I think, caused over-investment in new ways of extracting oil, which drove up production and drove down prices. (I mean, there was also a lot of investment in renewables, and I imagine that is also putting downward pressure on oil prices.)
I don't think anyone disagrees with the idea that oil is a limited resource and will become more rare and thus assuming continued demand, more expensive as time goes on? That's not what 'peak oil' was about.
Peak oil was this idea that both supply and demand were largely inelastic. In that case, when those curves crossed, you'd have the figurative unstoppable force and the immovable object; the price of oil would climb out of control, the economy would grind to a halt.
The primary thesis of 'peak oil' was that we couldn't extract more oil from the ground than we already were extracting. Through fracking and the exploitation of oil shale and oil sands... we did, in fact, extract more oil.
Turns out, the supply of oil is, to some extent, elastic. Yeah, we're going to run out some day, but with our current tech... it's starting to look like we might have trouble dealing with the atmospheric carbon output before we have serious trouble with the supply of hydrocarbons.
See, the 'peak oil' people were wrong; turns out that if you are willing to pay more, there's a lot more oil you can extract (albeit at a higher cost)
I actually think it was a self-defeating prophecy in a way. The peak oil folks actually had some mindshare for a while, and there was a lot of investment in more expensive ways to get oil out of the ground that had the assumption of long term oil prices being over a hundred bucks a barrel. This, I think, caused over-investment in new ways of extracting oil, which drove up production and drove down prices. (I mean, there was also a lot of investment in renewables, and I imagine that is also putting downward pressure on oil prices.)