I'm sure NSA has tools to attack air gap computers too.
I reckon a startup could do it.
Dont know how true it was or is, but I've seen some of these devices now advertised online. I'd provide a link if only Google & Bing would deliver the results, and were also psychologically engaged in warfare on the population.
https://en.wikipedia.org/wiki/Van_Eck_phreaking
https://en.wikipedia.org/wiki/Tempest_(codename)
Though for a second I thought you were going to talk about the mythical TV licensing detector vans :)