If the global energy business operated according to the principle of what helps everyone the most- getting the whole planet to a cheap and abundant energy source as soon as it is possible, in order to create the greatest public good- rather than indulging corporations in extracting the very last penny of value out of old ways of getting energy regardless of the detriment it might cause society- I think we'd regard Greenpeace's lobbying as one of the contributors to that ultimate resolution.
You can't blame activists for the inertia of entrenched robber barons. Agitation doesn't always get the best results at the time, but in the long view it's one of only a few impulses that move the juggernaut not only forward, but forward in the correct direction.