Putting the planet aside for a moment, the unnecessary death and illness they've inflicted on the human race will be staggering.
But there is no reason to hang on to the old, dirty technology if there are now better alternatives. And if the economics work, the market will follow, as it seems to be doing. You can't fake lower costs.
Nuclear should have replaced coal decades ago but the economics didn't actually work, even though the environmental benefit would have been real.
Mass death of species too numerous to name, the biosphere itself, property damage from rising ocean levels, the soon to fail air currents, all the damage and death from extreme weather events, all of it. All of it could've been fucking prevented and it wasn't, because profits.
I wish I believed in hell for people like this.