In one sense, energy doesn’t matter all that much to what’s coming. Once debt reaches a certain level, oil can be $10 a barrel or $200, and either way we’re in trouble.
But the cost of energy can still play a role in the timing and shape of the next financial crisis. The housing/derivatives bubble of 2006 -2008, for instance, might have gone on a while longer if oil hadn’t spiked to $140/bbl in 2007. And the subsequent recovery was probably expedited by oil plunging to $40 in 2008.