I would think waaaay more people have heard of Snowden than of RMS. If a movie about RMS will get made, than in the shape of a crowdfunded community project.
Well, yea. Because he metaphorically died in terms of US politics. It's one of the few bipartisan issues that sticks out like a sore thumb to the public eye.
I hope it's far in the future, but we'll see how the media spins it when Stallman dies. They can easily sell him up as some Godfather of computers. Or it can just be a small whimper in the corner of HN. I'd still bet on something closer to the former, but it's not a sure bet.