I for one am glad. E3 has turned into a weird meta-event, with people only interested in who "won". The gaming audience (press included) act spoiled, spiteful, hostile and ignorant to the art form that is games. Since the big E3 conferences are primarily watched by an audience that doesn't care for Nintendo news anyway (unless they see them go 3rd party), why waste time, money and their quality work on ADHD Gametrailers dudebros?
The other thing is that really Nintendo is not very good at these conferences. There's always uncomfortable silence and tech f*ckups and weird dramaturgies.