The reason Arrangers cost more is simple economy of scale. If you make 100,000 Motifs, you are going to be able to sell them cheaper than the 10,000 PSRs.

And just to chime in on the 'sequencer acts aren't really playing' hijack........... Don't kid yourself, just holding down a chord and pressing a few buttons does not make you any different. We are all substituting, in one way or another, for the fact that we are too cheap/greedy/lazy to go out and form a REAL band with (gasp!) OTHER MUSICIANS!

Just kidding...... sorta.......