Yeah, Brian pretty much was the man in that band.
I mean, I know there's a huge pool of bigger Beach Boys fans than I who love the Brian years but also have high praise for the stuff from, say, 1968 through 1973, when Brian's influence receded and the other two Wilsons started to contribute more heavily. And I'll give Mike Love some credit for writing a pretty decent set of lyrics on occasion, in a kind of second-rate Chuck Berry/Eddie Cochran idiom. But Brian was the musical genius in that band.