A subversive actor only needs a lookalike of one or two people. And it's not like we can't duplicate a video of a doppelganger. So the analogy is lost on me.
The new tech allows to do the same on a massive scale. Yes Stalin had people working for him who would manually erase from photos the people he didn't like any more. It was possible. Photoshop's content-aware fill and various deep learning inpaining algorithms can do that at scale with a fraction of the effort.
The same way, yes it was possible to hire a lookalike, but a) the deepfake will look more similar to the target person than any lookalike can and b) you don't need to find a needle-in-a-haystack lookalike to generate a fake video of anyone you want.
Or, "the post has been carring messages to people for centuries, why is the Internet such a big deal?"
You make a glib attempt at a parallel that's not relevant to the topic in the article. The point of this article isn't that we now have a "mechanical" process to make faking easier. That's been known for awhile. The headline specifically calls out acting for the purpose of deepfakes, but the article goes on to discuss the troubles deepfakes can cause.
It's certainly arguable that doppelgangers made "deepfakes" easier in the past, but only easier to those who could hire the actor. And that this technology makes it so that hiring the doppelganger is unnecessary, but it's by no means easier like the printing press made copying books easier.
The real actor in a deepfake doesn't have to look much like the target person. The pool of usable actors thus explodes by many many orders of magnitude. Hence my comparison.
>I don't understand why this is such a big deal now
because, as the article points out, the actor in the deepfake isn't going to actually act out what the deefake is later going to produce. So this makes creating nefarious content possible by letting the actor read something harmless and then replacing voice and appearance with say, a scam or whatever else. You could hire an actor to read something random and then use deepfakes to make it look like a kidnapping to extort someone or whatever.
If you hire an actual human for the entire thing you'd have to clue them in, and pretty much every commercial business is probably going to not participate in something criminal. Deepfakes probably could scale one innocent performance up to thousands of potential malicious ones.
You know these scams where old people are being called and told that their grandson had an accident and you need to wire them money? Imagine that with video footage and 100% fidelity.
Here is a random agency where you can book real-life doppelgangers:
http://www.lookalikes.info/