There's heaps of instrumental stuff on radio but only if you like classical stuff. I dig some of it, e.g. Vivaldi, some of Bachs freakier stuff and (particularly) Rachmaninov who wrote seriously heavy piano stuff.
Unfortunately most of the classical crowd have their heads stuck up their arses and think that neo-classical/rock instrumentals are too vulgar to listen to and would rather listen to something really stuffy and (aaaghhh) relaxing. Forget that it's only really been in this century that composers of music have shifted into modes other than major and minor and that western music has taken up eastern influences with more unusual scales.
Then there's commercial radio stuff for non-musos which basically tries to plug directly into our labidos by selling sexy divas to us who may sing beautifully but have limited melodic imagination and would rather not be put to shame by the real (session) musicians they regularly play with and who write their songs for them.
Perhaps intricate melodies require too much memory for your average non-muso to appreciate, certainly complex stuff might take a little getting into. I've never like the fact that while plenty of magazines cater for the oversexed male, radio stations still concentrate on musicians who are noted for their physical appearance which should be irrelevant.
Radio sucks. If you want advice on whom to listen to you have to come to sites like this.