There’s also something to be said about being knowledgeable in your field and thinking you’re knowledgeable in all fields
Yup that right there is the core of this issue, happens to the best of us.
Fortunately it doesn't happen to me, I'm a CS expert but also a sociology expert so I know how to distinguish it
Livestreaming becoming commonplace was a big part of it. Why would a brand go through the expense of setting up a presentation and booth in E3 when they can name the where, when and how, in a much more controlled fashion, for much cheaper, to reach more eyes directly.
The primary purpose of E3 for them was as a marketing space so when a more convenient form of doing it appeared, it was done.