Whilst it could possibly be 'good for the developers' I think the thing that has to be remembered here is that taking up so much of your audience's mindspace so often can definitely lead to apathy in the end.
Like today's announcement. You see it on Twitter and think "I'm going to watch that." So you:
1) Find out when it is
2) Find out where to watch it
3) Find a way to fit watching it into your schedule (and if you can't get disappointed that you won't be able to watch it live)
4) Tune in at a specific time
5) Be pre-disappointed lest you be called a "delusional fanboy."
Over and over again, and it seems that for many it's been a 100% disappointment rate so far. However with E3 you could have all of those steps (excluding 5) completed in a short time-span; you could plan parties, buy a ton of snacks, take some days off work, and just generally get in the 'mood' of the season. Right now you have to be tuned in and waiting for announcements over a period of god-knows-how-many months, and you have no clue whether those announcements are going to excite or not if you're not if you don't basically spoil them for yourselves by following various industry Twitter accounts.
Basically the amount of 'labour' that one must do to watch and get hyped for E3 is much, much less than the 'labour' one has to do to keep track of, set the expectations of, and then watch all these tiny little 'events'. I can definitely see people getting bored of that, and perhaps even becoming resentful after a while which could lead to the opposite effect on 'smaller' games. There's this prevailing thought on Era that everyone is willing to "follow the news" and "temper expectations" and "take things as they come," which, frankly, is a ridiculous notion to me when we're talking about game announcements.