Hi,
here are my 2 Cents on this:
With GENOS, Yamaha already started a new line of keyboards. They moved to Linux as the OS of the main processor and to a new generation of sound chips. Important changes to the UI also happened.
Looking back, you could compare Genos to Tyros1, the grandfather of a new line. So a new Arranger-Keyboard will (hopefully) bring long awaited improvements (maybe USB-Sound, more Expansion Memory, Hardware Switches for Chord Looper etc.), but will not differ so much from Genos(1) as Genos from Tyros.
For the Expansion Packs, I would argree, that it was (1) pressure from the market and (2) they don't earn so much from selling them.
Rainer