I find this author's characterization of the history of C inaccurate. At the time, C was innovative. And its existence did enable computer science research, because with C, operating systems were finally portable. C itself was a worthwhile contribution to computer science research. Kernighan and Ritchie built upon prior languages, but they were able to distil what levels and kinds of abstraction were needed to implement portable systems programs. Many of the concepts in C existed in C's predecessors, but not in the same form we know them as. It's easy to under-estimate how novel that contribution is because so many of us think in C now.
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).
For a history of C from the source, Dennis Ritchie, read this: http://cm.bell-labs.com/who/dmr/chist.html