Personally, I think the arranger slump in the US is mostly due to how bad they do contemporary styles. While in Europe and Latin America, more traditional forms are still very popular, in the States the clubs are dominated by bands that play rock, alternative, and rap/hiphop/R&B. None of which are the traditional arranger's forte.

Few parents would buy a PSR for their kids today and expect them to LIKE it. They want something that can do some Beyoncé, DMX or T-Pain. And that AIN'T the arranger. It's the WS/Groovebox. Europe and Latin America, singalongs are still popular, people like the familiar songs they can sing along with, but ask any kids the words to a traditional song, you get a blank stare. But they know ALL the words to some rap song, or an emo/angst rock tune...

Just look at the Billboard Top 30. I can't think of hardly ONE song that an arranger could do. Now compare that to the Top 30 in say Germany, or Mexico. I guarantee there's a LOT of songs performable on an arranger.

Until arranger manufacturers incorporate some of the features and sounds that make making hiphop and techno as easy as a WS or computer rig, don't expect to see arrangers regain any ground over here...

JMO...