Peak oil is certainly not a scam, we haven't even come close to burning up half of the oil in the world. However Peak oil means we have reached the peak of economically extractable oil.

From now on there will be less and less oil that is extractable at an economically viable and energy efficient manner.

There are many fields even in the United States that are deemed empty but still contain millions of barrels, the problem is that to extract the oil the cost in money and energy would be too steep, at some estimates one barrel of oil extracted would cost 3-4 barrels of oil consumed in the extraction, plus the costs of production which are always large at the best of times.