What are twelve-note rows really for?

‘…I don't need to use serialism to…achieve a unity between the motifs’ says David Matthews in his interview with Mark Doran (Tempo, Vol. 57, No. 223, January 2003, p.11); and most composers would say the same. After all, the motifs and themes of the first movement of Schubert's Third Symphony are so integrated that even the accompanimental cliché of repeated quaver chords turns out to be motivic and the whole of the ‘Unfinished’ is based dialectically on the tonic and dominant versions of a single three-note motif and their sublation. And in his Ninth symphony, Beethoven manages to base not only themes but key-successions, too, on a basic group of four notes and finally even creates that shattering dissonance at the start of the finale out of a simultaneous sounding of its notes. Or is that already proto-serialism?