The stone didn't finish because there were no stones left.
The age of oil will finish for the same reason. Technological progress.

We are witnessing destruction of one of the largest global monopolies - OPEC.
Hopefully other monopolies like the global currency monopoly by Federal Reserve will also be destroyed by cryptocurrencies.

However if you think that Federal Reserve or OPEC is bad, wait and see what happens to Google or a Facebook once they merge with governments.
We need to build new technologies that will challenge new monopolies.