They aint taking off because of price full stop. For the price you can get a DAB radio, you can have yourself a mid-range hi-fi with like 240watt RMS output and 3 cd's etc...
And the fact you can get all the crappy channels on digital TV does not help. And the fact that all the stations any1 ever listens to are available on FM/AM radio's who is going to move over to DAB to hear birds singing