Because, I don't want to waste money and nor does anyone else in the country including the owners of 100 million fm/am radios and 30 million cars.
We should stop the idea of introducing digital radio immediately. I have one digital radio in my house, it doesn't work and I don't even live in a rural area. I have 4 FM/AM radios in my house plus another 2 in my and my wife's car. They all work perfectly and don't need repalcing. Why should anyone waste money repacing perfectly good radios with DAB radios that don't work any better and generally much worse.