The appalling reduction in bit rates, due to the greediness of OFCOM wanting to sell as many broadcast licences as possible, is a scandal. The fact that DAB was antiquated before it even started broadcasting (MP2 FFS) and that they wildly miscalculated the problems that would be caused by weak or multipath signals, means that it has never been fit for purpose.
The early demonstration broadcasts of Radio 3 were reasonably good, and similar in quality to the FM service (though with more compression). Subsequent broadcasting on DAB has been a sad joke. The uptake of receivers for the first 18 years of the service was laughably small. The coverage around much of the UK is still abysmal.
It's only the huge advertising push over the last few years that have actually persuaded the hoi polloi to part with their readies for new receivers. Sadly, when they get their shiny new DAB box home, it mostly remains switched to FM mode or relegated to a cupboard, because the DAB side of it just doesn't work.
Since mobile data coverage on most networks is better than DAB coverage, and because 128kb/s MP3 sounds better in a car than the bubbling mud of DAB, that's where the listeners are going. Early last Autumn, I listened to the output of my on-line radio station all the way from Colchester to Turin (with a break in the Chunnel) using my mobile phone coupled to the car radio by bluetooth. There were a couple of dead spots in the wilds of rural France, but for the most part I got great reception.
If I was listening on DAB, that simply wouldn't have been possible....