Other countries, on the whole, tend to have much more traditional musics popular with both young and old. Although the young in Europe love going to raves, they will also happily join in a singalong at a bar or restaurant. The US has no singalong tradition (or very little of it), so arrangers are given a pretty wide berth by any young player.
After all, forty years ago was the SEVENTIES (scary, ain't it?

) and, while perhaps disco gets good shrift on modern arrangers, rock is definitely weak, and don't even get me STARTED on how poor 80's, 90's, and especially anything from this century is on an arranger...
Yamaha's DJX proved how popular arrangers could be for the young if styled and voiced right. Sadly, Yamaha dropped it like a hotcake. Obviously, the arranger division is completely incapable of relating to younger players (or anyone that doesn't want EXACTLY what they currently make, for that matter!), and so it all goes down in history along with all the other 'Whatever happened to...?' products.
Buggy whips for a Model T generation.