I agree with the first part, but am not so sure about the second. If the breaker-upper doesn't want to break up, then I can believe that he or she will communicate more; but, if the breaker-upper does want to break up, then I can believe that he or she might withdraw and communicate less. (I'm not sure which of these you meant by "heavily weighted towards the side doing the breakup".) Certainly, I have seen both kinds of behaviour in my two failed relationships.
EDIT: As overcast (https://news.ycombinator.com/item?id=10933670) points out, it's strange to speak of the breaker-upper as not wanting to break up. The distinction I'm trying to draw is still a bit slippery, but I guess I mean to distinguish between wanting to break up (where your partner probably couldn't do anything to convince you to stay) and feeling that you have to break up (where your partner might be able to change to convince you to stay). Jtsummers (https://news.ycombinator.com/item?id=10933737) puts it better.