Isn't this thread very 'rock-centric'? I reckon there has historically been fierce competitiveness in jazz. Even pre-jazz, rag-time and barrelhouse piano players would play (sometimes literally) head-to-head in cutting contests. What about jazz horn players, - if you wuz gonna try sitting in on an after-hours session in a Harlem club in the 'forties, - you better have some chops. And what about Chicago blues clubs in the 'Forties and 'Fifties?

The 'cutting' thing has never only been about guitarists, AND goes back way before rock n' roll, in my opinion.

Cheers, all
Karl