Energy return on investment.
Yes there is a vast amount of resource under the ground. These can be divided fairly neatly into two - minerals that are used to build things /grow food, and minerals/liquids/gas used as a source of energy. Extracting anything from the ground uses energy. An energy source that use more energy to extract than it usefully provides is not an energy source, it is a sink. We may get to the point where drilling for oil is a net energy sink, because oil is so much more useful to society than coal, that we are prepared to still extract it using energy from coal at a net loss. However, we will never mine coal at a net energy loss. And coal is still the single biggest source of energy in the industrial world. All the easy sources of energy are mined first. That means, unless technology improves exponentially, the net energy from each KWh of energy extracted must decline, relentlessly, regardless of how much is under the ground. All the easy sources of all minerals are also mined first. They need ever larger amounts of energy for each Kg on mineral extracted over time, unless technology can improve exponentially. And the mining of energy needs ever more kg of minerals as people dig and drill deeper and further.
So over time, we spend more and more energy extracting the same amount of minerals, and more and more energy and minerals extracting the same amount of energy. More and more of the global resources of both minerals and energy are used to keep the mining industry expanding, and less and less is left over for the rest of society.
This is not sustainable. Long before the total energy budget peaks, industrial society peaks. Demand for the ever more expensive minerals and energy cannot be sustained, the price falls below that required to invest in further mines and oil fields in ever more extreme environments, and investment collapses. Then industrial society collapses.
We are at that point. All the major private oil companies are way past peak production, and are cutting their capital budgets because they cannot find more oil to drill at an affordable price, even though the price rose FIVE FOLD in a decade.
Yesterday, the official estimate of shale oil (as in fracking) resource in California was cut by 13 billion barrels, or 95%. That oil is still down there, but it is going to stay down there. For ever.