I've been in the energy and minerals exploration game for a few decades and I've seen all manner of odd things said with a straight face by all kinds of people.
While I have no a priori knowledge about yourself specifically, I have seen people regularly dismiss notions that minerals and energy get increasingly hard to find and will cost increasingly more to extract.
Peak oil is a specific discussion about oil resources and one that is often dismissed as (not the statement you made) "rubbish, we were supposed to run out, that never happened" etc.
The claim in the nineties was that given demand for oil was ever increasing there would come a time when no ordinary individual would be able to afford oil .. and we do appear to be on that trajectory in the world, even if certain demographics are sheilded from that reality.
Your GP comment misframed that and described that as a common mistake mistake in predicting the future.