Funny thing is, regional-large market DAB in theory would work well here in the States. Think about it for a second; sell that transmitter site, or do away with that expensive tower lease and the need to light/monitor a tower. For Class B and C stations, lose that expensive power bill, maintenance costs, and capital expense of having to replace expensive transmission equipment. All you need to send the common DAB site is audio. Cost of transmission and maintenance is spread across all the streams, and much less variable than being responsible for your own site. Everyone in the market has equal coverage.
But it will never happen, because of the old way of competitive 'it's my signal-thinking'.