Dreamer, I agree that the bass player makes the right thing for the groove and that arrangers lack this kind of interesting bass figures.(especially those with several strings sustained at the same time) Bass is a very important rhythm element so it is a very crucial thing for keyboard styles. Listen though what happens in the chorus. The bass player simplifies his lines a lot but the groove is still there! Listen to the bass in the end of the song. It's nothing special about that tone. The bass sound is kind of picky and low in sustain and I think a keyboard can come pretty close to that sound, only choose a pick bass and then set the EQ rather dark. Of course in this case the bass player plays rather advanced figures so it would not sound the same and with a cheesy pick bass guitar sound it wouldn't sound as good. Even though the bass sound in this song is not very special IMHO, it is not including a muddy low end like the bass guitars in some arrangers.