It's not just a matter of the cost of switching either.
I own a synthesizer (OP-1) that has a built-in FM receiver for sampling and for fun. Creativity-vise, it's an ingenious feature. Essentially, you can pull new sounds out of thin air whenever you feel like it. No need to connect or set anything up.
Why does it work so well? The receiver is cheap, the radio service is free, the way it works is universal and it's something reliably present in most countries. DAB sounds like it will not have any of these properties initially, and it will never have all of those properties.
My point is that the combination of those features enabled companies to create innumerable innovative appliances that use radio (from cheap radio clock to my Swedish synth). Switching to DAB will not only make existing devices useless, it will also kill the possibility of having new innovative applications in the future.
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This kind of stuff bothers me, because it's increasingly common these days. People replace reliable, working technologies with something "modern" and claim they are making progress, while completely ignoring higher level architectural considerations.
Consider another thing: the money spent on this kind of stuff can be instead spent on making better Internet infrastructure, which can house digital TV, digital radio, digital phones, but also websites, online games, (soon) connected VR spaces, and things we can't even imagine yet.