Well, how about the fact there's an absolutely enormous, untaxed negative externality? It's implicit - normally you tax something to reduce use of something harmful. Renewable energy would be far more competitive if this was factored in.

Fossil fuels are causing incredible economic damage - but in a way that isn't captured by traditional economic models. It's going to have huge costs to future generations - if we taxed it, not only would we get off fossil fuels faster, we might then have extra cash around to soften the blow when it inevitably comes.