There were reasons for those aborted activations.
I mentioned above that the Main Street theater project has structural issue making it impossible (or way more costly than anticipated).
Avenger Campus did come about. I assume you mean its E-Ticket, whose first iteration was killed because Ops didn't want another low capacity ride. So, it was delayed to find a new ride and then the pandemic delayed it. It's still supposed to happen.
The Festival Pavilion was put on pause due to the pandemic lockdowns. Then they changed their minds about what to do several times. They still went ahead and tore down the Northwest quadrant of Communicore. And then went ahead with JoW and a revamped Festival Center. So... still a Festival Center.
Spaceship Earth and Mary Poppins were put on indefinite hold due to the pandemic. Disney hasn't said they're dead dead.
But, most of these have the same thing in common: The pandemic.
Well... we're sorta out of the pandemic, and guess what Disney has been talking more and more about on this side of the pandemic: PatF retheme. It survived the pandemic whereas other projects didn't.
It's coming.