I am familiar with the development of musical styles, where the styles usually start out in smaller ensembles, with limited notation, relying heavily on improvisation, then growing in size adding more notation, with fewer and fewer improvisational opportunities. You can see it happen in all kinds of styles from Argentine tango to blues even western swing. What kind of puzzles me is that rock and roll, never really developed past the small ensemble. After a little searching, the only large bands I could find were Chicago and Blood Sweat and Tears. I wonder why this is? I was thinking it might have to do with the guitar technology, but then there are plenty of big band blues and funk groups.