I visit three TSTO forums, two regularly. Both of those two have experienced a palpable decrease and comments just like yours are common to all.
There are several valid reasons I can think of, yours included.
Here's another one ... I mentioned in another forum that I think the little "leaks" of information we used to get from spAnser kept us energized. Lots of our time was spent theorizing what the smallest tidbit of his information might lead to. That's a reason for "teasers" across the entertainment industry.
Suddenly, that entire chain of info has been cut off. There is nothing to chat about between updates. It is, to me, as if a lot of the excitement and suspense just evaporated. Now it's nothing but "ho hum" until an event strikes out of the blue.