"GSMem takes the air out of the gap and will force the world to rethink air-gap security,"
"Air gapping" has always been about vector mitigation: Stopping the nasties getting in to stop the good stuff haemorrhaging out. In order to reasonably protect a computer which has not been infected with their malware from remote surveillance, the machine must be enclosed in an opaque soundproof Faraday cage which ideally would be quarantined in the turbine hall of a power station on an unmanned but extremely well defended military base on a remote and inhospitable planet. Compromising emanations have been an old and widely known problem since at least the the electro-mechanical era. No "GSMem" necessary. If your site isn't secure, your equipment isn't secure: "Airgapped" or not. Inevitably. "GSMem" and other malware are superfluous to this.
Perhaps the researchers should Google "compromising emanations" for a better understanding of the situation and "TEMPEST" for an overview of the Yanks' mitigation strategy.