This video offers a quick view of the long distance travelled from the first arranger (auto-accompaniment) keyboards to current models. Specifically, here is a quick comparison between what it could be considered as the first "flagship" arranger model from Yamaha (the PS-6100, released back in 1984 for a price comparable to a DX7) and its current professional model, the Genos (released in 2017). Some "comparable" instrument sounds and styles are shown.
The PS-6100 featured two YM-2164 4-Op FM sound generators (the same chip as the DX21, DX27, DX100 and FB-01, among others) to offer 16-note polyphony. Contrary to its synthesizer counterparts, the presets aren't editable at all. It mounts also a RYP4 chip (from Yamaha's RX series) for the PCM drum and percussion sounds. Some of the presets are "solo" sounds (monophonic). The keyboard has aftertouch only for solo sounds, and it's not velocity sensitive. It hasn't either pitch bend/modulation wheels, but includes an interesting analog chorus effect, harmonizer and (sort of) multi-track recording and rythm composer. the keyboard can be split in up to four zones (chords, lower, upper and solo). Each accompaniment style has two variations and three fill-ins, but no intro/ending.
Enjoy!
EDIT: I've noticed than in the process of generating the video file, many of the the audio clips of the PS-6100 haven't rendered properly, generating some audio clicks and/or jittering. I'll try to fix this and upload a new version.