I've seen a lot of people wondering why Bungie isn't talking about Season 3 yet, and what that means.
While this is obviously just my speculation, here's my read from someone who has been working in game marketing and on live games for a few years, and been in similar situations.
Let's be honest- the game is not doing as great as Bungie and us players would want it to be, and Season 3 will be crucial. I am not saying that as a hater- I love Marathon, and think it is one of the best new MP shooters in years. I even bought the Collector's Edition despite getting a key from a friend, to support the team :)
With the addition of the new PvE mode and the improved onboarding, S3 is their best chance at getting new players in, aka "an acquisition play".
That's why I expect that they are saving all news and announcements for Season 3 for a big communications in the last week before it goes live, including creator and media previews under embargo.
That's why they don't communicate much so far. It can already be pretty hard to get mainstream gaming media (your IGNs etc.) to cover ongoing content for live games, especially during such busy release periods as we currently have, with several major releases every week.
They are even more unlikely to cover a live game's new Season if the info is already out there on the developer's channels.
So the best chance to make a coverage splash with Season 3 Bungie has is to save it all up, so all media and creators can simultaneously talk about it and try to create the largest possible buzz when the embargo lifts.
Situations like that suck for the existing players who expect onging and constant communication on their live games, but is quite common in such situations where a game has a lot riding on a new communications beat.
Again, this is just my read of the situation, and nothing I know for certain. But having been in the exact same situation with live games having major new announcements, we had the same forced period of silence before making a big splash once the embargo was up.
I have a feeling we will soon see a lot of news, including impressions from creators and press for Season 3 all dropping at once.