Adding more voices does not always improve things. I have often gone to see a single performer and when I bought their record, found I was disappointed to hear other back-up musicians.
It's fun to play with others and I enjoy playing in a duo, trio...up to an eighty piece orchestra and choir, but I also like playing by myself.
As has been mentioned, a smaller group often earns more, but we usually have a minimum per person , with exceptions for good causes or fun gigs. The Orchestra and Choir pay nothing, in fact we pay an annual membership fee.