I too say "And???" Also, who ever said that Schoenberg said that we "should begin all over again"? Not Schoenberg, for one, AFAIK.
As for "In each generation .. . the past is indelibly printed on our central nervous systems. Each of us is part of a vast physical, mental, spiritual web of previous lives, existences, modes of thoughts, behaviors and perceptions of actions and feelings reaching much further back than what we call history," well, for sure.
The problem is that if we're talking about music, we're talking about a lot of different ways of making music over the course of time, while Rochberg, when writing music in the pastiche-of-styles mode that he more or less came to favor because he found Schoenberg's ways of music emotionality invalid, tended (to use a term that usually I don't like but that fits) "privilege" ways of making music that date back to, at the earliest, only the mid-18th Century.
Also, the turning point for Rochberg, previously involved in writing music in what he felt was a Schoenberg-influenced manner, came by his own account after the death of his young son and his resulting inability to write music in his prior manner that in his view adequately expressed the intense emotions he felt about his young son's death and that he wanted to convey in music. Well, if that was how Rochberg felt, that's how he felt. But what a strange thing to say or imply of a composer, i.e. Schoenberg, whose music frequently was emotionally eruptive to an extreme. What, for example, of Schoenberg's String Trio, which scarifyingly conveys the composer's near-death experience from a stroke? And "Ewartung" isn't exactly a walk in the park. One could say that there is little or no Schoenberg music of any period that is, say, amiable, but then he wasn't an amiable guy.
I should add that while I tend to dislike the often geschrie-heavy music that Rochberg wrote in the first flush of his conversion/reversion experience, I've recently discovered his expertly crafted piano music, which so far isn't that way at all.
I think the context of when the quote was taken is important. His string quartets cyle, which I find quite remarkable, follow this struggle of breaking with the past, then reconciling with it -- the earlier ones having that geschrei, the latter ones quite different, almost lyrical.