I take your point, Leeneia, but Johnny Mercer and Hoagy Carmichael were songwriters who "took out the middle man" and performed their own music, and Johnny even started his own record label.

It's true that most bands of a particular type sound pretty much the same, and that good songwriters are few and far between, but if you want to talk about "producing the same kind of thing every time", keep in mind that back in the days before "singer songwriters" not only did the bands tend to sound alike, they all played the same songs...