Doesn't matter if the emissions are stopped now, still need damage mitigation because the planet is already hot (we should also reduce emissions of course)
Also the whole megacorps pollution thing is about as problematic as the personal carbon footprint idea. If you think the companies are causing all the pollution, it's easier to keep consuming the fuel and goods that those companies oil and energy produces. Like for example if you live somewhere in the western world and think that one of the world's largest polluters, China Coal, isn't affected by your consumption habits, unfortunately you're pretty likely wrong.