Well, it's not from any lack of trying on Dick's part. That's for damn sure. The clip I just reposted demonstrates that. Ultimately, I think Nick's ego being wounded by Ralph's chimpout is dictating his response to all this more than wanting to please Dick. Nick does not respond well to criticism, at all.
If Dick really wanted them to be all bosom buddies again, he should work more on convincing Ralph than Nick. I never understood why Dick doesn't get that the whole thing fell apart because of Ralph. Dick is supposedly Mr. "common, take a joke, bro." If it weren't for Ralph chimping out over Nick's milquetoast response to the shart, the three of them would probably be all copesetic right now. Dick is going about all this the wrong way, but maybe he resigned himself to the idea that getting Ralph to show contrition on anything is a lost cause.