Could it be that the AM band survives FM, Pandora, DAB, satellite and the internet threat, only to fall victim to interference from smart phones and digital devices?
In addition to the tablets, smart phones etc, more and more household appliances are utilising inverters for voltage regulation and speed control in an effort to improve efficiency and earn more energy stars.
In commerce and industry, inverters and variable speed drives are widely used for motor control, to reduce starting currents and offer other control benefits.
These forms of interference are only an issue on the AM broadcast band with little if any effect on the FM band.
This article from the New York Times ponders the problem new technology creates for AM broadcasters.