They cannot announce games as fast as anyone would like.
Substantial updates on a game's development can't be more than every 6 months to a year without putting the team in a constant state of promotional material generation.
Major new first-party titles were basically reserved to E3 in previous years. If you spread that over a whole year of Directs, it's unlikely any individual Direct will even have one, let alone a huge blowout of anticipated new games.
We have release months for Mario Kart and Smash Bros. You won't get more detailed than that.







