Sheer paranoia at the possible connection to the word 'arranger', in all probability...
You've seen how many manufacturers like to leave off the word 'Arranger' from the front panel, heck, even my G70 is a 'Music Workstation' according to the marketing wienies at Roland
It appears it is the kiss of death to any WS sales, arrangers being viewed by the young as schlager and schmaltz machines...
In fairness, as well, the whole 'loop' mentality doesn't really think in terms like 'Fill' and 'Intro', simply in separate 'chunks' of music that you trigger as needed. The Yamaha MotifXS, for instance, has nearly everything you would need to actually use it as an arranger (but without all the user friendly things like lyrics and Music Finders, etc.), but the way they control the loops is MUCH more DJ-like than arranger-like. No conditional loops (like a fill that automatically goes to a Variation or an Intro), but you CAN do almost everything by hand.
I guess that is the major paradigm shift between arranger playing and DJ-ing... arrangers make the transitions for you, DJ-ing is where you primarily PLAY the loops, rather than the music they contain.
Sooner or later, arrangers WILL have to incorporate loop tools and arpeggiators, or nobody left alive will use them, much but I am not really expecting it. Seems all too obvious that arranger makers are only TOO happy to let R&D stagnate, and keep the two types of keyboard separate... double their profits! If you need an arranger AND a loop/arpeggiator keyboard, you have to buy TWO keyboards. Money makes the world go round...