Ash has gone through plenty of things. He's seen the whole Kanto-world and has been the League Champion. He doesn't have to talk, he has already reached everything. Now, he's not the best anymore (that's supposed to be you) and he disappears. He has nothing to say, and he doesn't have too. I think Lance's quote when you beat him would be more appropriate here, but of course, then he would have talked.
There is no need for words now.