Clearly something is going on, it's not as if Mercedes would mention something if they felt it wasn't the case. Anyone that thinks otherwise and it's being done just because the fans are "bored" is delusional. They did it to Fi in 2012 Bahrain. Bernie is a ruthlessly shrewd little man.
Some statistics I've dug up.
Suzuka 6
Singapore 16
Monza 31
Spa 26
The average TV coverage for Mercedes throughout the year has been about 20% of the TV time.
....................................Malaysian GP Chinese GP Bahrain GP
Amount of time on-screen ....... 20:29..........10:27.........22:08
Percentage of race................ 20.3%..........10.5%.........23.3%