I've heard a few people say we've already drilled all of the easy-to-get oil, so the next civilization may not develop using oil.

But maybe all that means is they will master some other technology that we did not. It seems like previous civilizations have mastered technology that we cannot figure out.

> It seems like previous civilizations have mastered technology that we cannot figure out.

That was true for a while (e.g. in Britain they spent 500 years figuring out what the colonising Romans had done to try and recreate their advances), but I don't think we're now in that situation. The best thing would've been to mostly convert electricity to nuclear in the 1980s, as by now we'd be handing over ultra advanced nuclear designs and low carbon to the future. Now we're just playing catch-up with the 1980s.