It is my observation that most solo acts simply couldn't handle playing in a duo or group if there was a lot of extemperaneous playing "off of each other" going on.
Take a look at the post of the "4
Hammonds". You don't get that kind of interaction when playing a solo job on an arranger.
There's nothing like the unspoken communication between musicians of equal ability when they trade fours or interact in that fantastic "shoot from the hip", often unrehearsed way.
In those cases, there's nowhere to hide, and nobody is going to carry you. You produce or get the hell out of the way.
This is my opinion and I'm not going to change it....I wouldn't expect anyone believing the opposite to change their beliefs, either. It's kind of like the previous discussions about the difference between musicians and entertainers, and we've already been there.
Here's hoping we all enjoy success and a sense of accomplishment; however we define
it.
Russ