My understanding is that the State of the Union is to inform Congress of his opinion on the situation of the country and what he feels is need, it is not actually to address the American people, though it's been televised for quite some time.
That is why Pelosi wants to wait until after the shutdown, she knows full well he will make a case for the border wall and since its been televised in the past, she doesn't want his information to be conveyed. Can she give a rebuttal to the state of the union??
IMHO he has made this a huge focus, and now people will be tuning into the state of the union, because of the controversy. Score one for Trump.