This is backward: the way the incentives are built, anytime the market value of $reward + $fees BTC is $value, the miners will spend ($value - $margin) * %total

This is backward: the way the incentives are built, anytime the market value of $reward + $fees BTC is $value, the miners will spend ($value - $margin) * %total-of-pool to mine that block. It could only consume 'all excess energy' if the block reward is absurdly high, which it isn't.