The station I've been listening to, 3FM, had their annual 'Serious Request' charity drive in the week before christmas. Three DJs were locked in in a glass house and had to make radio for 24x7 hours, while not eating. The public could pledge money to request a song to be played. They collected over 7 million euros for the Red Cross, which is no mean feat.
During the drive, they couldn't play all the records that were requested. So from Christmas to new year's eve, they've been playing the "Top Serious Request": a hitlist of all the records that were requested, with the most-requested ones at the top. And it's nothing like the usual radio they make. It's mostly music (instead of the incessant bantering that some DJs seem to be fond of), and the spread over the spectrum is pretty wide.
People paid good money to hear these records. So why is the regular radio not more like this? Surely you could gain a tremendous audience by playing music from this list -- it's what people really wanted to hear.