Power consumption will keep growing (in theory) up to until it reaches the threshold for bitcoin (21 million – about 18.5 million have been mined to date) - once the mining effort exceeds the value, this is an effect of proof of work, of course, there's no incentive to mine more. So it's unlikely they'll mine all the bitcoin.
It's all a bit made-up, of course, but I have combined all my YACF posts-to-date to produce a non-fungible token. It's yours for £1,000,000.