I respectfully disagree with The Economist. Their analysis does not appear to handle the simple matter of "On" / "Off" switches. They seem to have missed a point during editing:
Planes far out at sea keep in touch using VHF radio, and the newer ones send ACARS data continuously via satellite.
Depends on the options chosen by the airline, doesn't it? I don't think "continuously" is correct, based on what folks who understand these systems have presented in this discussion.
I suspect they meant "HF radio" for planes "far out at sea" since VHF is line of sight. On the other hand, how far from shore "far out at sea" means could depend upon who is reading the article.