We're never going to run out of oil, just like we're never going to run out of gold or silicon or gravel or any other mineral resource. But as supply eventually declines the price may rise enough that petroleum can no longer feasibly be used as a vehicle fuel or chemical manufacturing feed stock.
You and the grant parent are arguing about a technicality.
"Oil prices being so high that oil cannot be used economically for anything" vs. "Actually running out of oil" would have the same consequences on modern society.
>But as supply eventually declines the price may rise enough that petroleum can no longer feasibly be used [...] //
It can still feasibly be used by those who own the oil stock itself. It's not the inherent cost that is increasing only the market price. As the price rises the market should work to ensure that every last drop of oil is bled from the Earth. If the price goes to high then [in a perfect market] it will drop back to ensure maximum exploitation.
It's only a falling price below the production cost that makes it infeasible to extract surely?
Not really. As oil grows scarcer it becomes more expensive to extract, regardless of whether you own the mineral rights. At some point the price will rise high enough that it's cheaper to substitute other goods for petroleum. For example liquid hydrocarbons can be manufactured using the Fischer–Tropsch process.
