I agree that civilizations (including humans) are unlikely to completely wipe themselves out, but it is not at all certain that we could recover to our present

I agree that civilizations (including humans) are unlikely to completely wipe themselves out, but it is not at all certain that we could recover to our present technology after a cataclysmic event. Once we mine out all easily accessible fossil fuels, we'll cross a certain point of no return. After that point, a 19th century type industrial revolution will no longer be (easily) possible. Let's say a truly cataclysmic war happens and we just lose access to modern technology. Would we be able to regain it at some point? Could we rebuild a modern civilization without having access to the most energy dense and convenient fuel known to us even today? Sure, we wouldn't go extinct, but if we are no longer able to travel beyond our own planet, we may as well have filtered ourselves out from the galactic stage.