Malthus's ideas was something different - that people will breed till they run out of food which basically hasn't happened.

People think of different things with peak oil. At the basic level production will peak - with a finite resource you can't keep increasing extraction for ever. On the other hand people sometimes link it to running out of oil which probably won't happen - instead we'll move to renewables because they will be cheaper and greener.

Just as Malthus observed that the land in the British Isles was a finite resource. Malthusianism is a trope in macroeconomics.

I am not claiming anything in favor or against the theory of peak oil. I am just saying that the challenges posed by a technological overhaul are very well described in the Peak Oil literature.