Let's face it, the BTCC hardly gets enough viewers to fill a people carrier - no one gives a flying flip what happens to a bunch of uncharismatic 40 year-olds!
In all seriousness, it clearly doesn't bug F1 audiences much. TV figures remain up, and the sport can afford to go to circuits that are almost empty (Turkey) and yet still generate a £1bn a year in income. We might not like it, but it's still making them all a large fortune!!