I think there are times when a rhythm section creates a "blank" canvas for a soloist to paint on. That is, they try to create a good feeling, provide harmonic support, etc. but without interacting a great deal with the soloist. Other times the rhythm section provides the feel, support, etc. but is more active in "reacting" to the soloist and feeding him or her ideas. Actually, there is no such thing as a "solo" unless everyone but the "soloist" stops playing! It's always a group solo really with one voice in the foreground as being of primary importance.
I prefer to think of a group performance as a conversation with ideas tossed back and forth between all members of the group. I love to accompany (comp) for other players but I usually try to be a part of the solo rather than comping for the soloist. With a secure player, I like to toss him or her an idea to react to, whether rhythmic, harmonic or melodic. Ultimately, the music created by a group of people who are "tuned in" to each other is an experience where the whole is definitely greater than the sum of the parts!
My final thought on this subject regards soloists who don't listen to the rhythm section. In this day of playalong recordings (which are a terrific practice tool), there are too many players who are used to a playalong not reacting to them and so consequently they forget to really listen to the rhythm section. When I detect this kind of attitude, I go into playalong mode, that is I just try to do my job of supporting the soloist with the correct harmony played with a good feel and I turn my thoughts elsewhere because I don't need to consciously think about doing that, I can do it on automatic pilot! Fortunately, good players know how to interest the rhythm section in playing with them - leave space, do something rhythmically interesting and react to ideas the the rhythm section offers!