You are rationalizing: C was not "novel", it was pretty much BCPL-light. There also were portable operating systems before UNIX, some of them were written in PL/1 and FORTRAN.
Adding structures or for that matter pointers to a programming language was not "novel" in 1970.
The sheer success of the UNIX and the myth it has built, has many contemporary programmers thinking that everybody else punched cards with flint tools around the bonfire. Even MULTICS, a very innovative and in many ways wonderful OS has gotten a bad rap because of the UNIX-fanboiz cult-building.
Dennis, Ken & Brian broke ground, but very few people can correctly say what new ground they broke. (Hint: namespaces, file structure, what a file contains).
