Other than legacy music, oldies, all that stuff, arranger manufacturers have mostly ignored contemporary US music. This is OK in Europe, which has a VERY strong tradition of sing-along music, schlager and traditional favorites. But in America, other than clubs that cater to the, let's just say more 'mature' crowd
, the music is very contemporary, whether urban - hiphop, rap & modern R&B, or contemporary rock - emo, alternative, that kind of thing.
This is, IMO, why the arranger is not pre-eminent over here. The manufacturers, with their sales base already well established in Europe, seem unwilling to invest the considerable amount of money and time it would take to develop these modern styles (and the nature of modern music is that it changes MUCH faster than legacy styles).
There's nothing intrinsically wrong with the technology, simply that the content has not been 'Americanized' except for older styles - classic R&B, country and western, classic rock, jazz, Motown, that sort of thing.
It's a Catch-22... They won't make the content until there are enough sales to warrant it, and there won't be much in the way of sales until the content is created...
What's a boy to do..?