You must not have followed since the beginning. They said numerous times during that stretch that they were building a coherent story that would end with the 3rd Avengers movie. They pretty much had everyone locked into contract until then. Endgame came about when they realized the story was too big for everything they wanted to do with one movie. Hell everyone knows there's a lot if filler in Endgame.When we were in the middle of phase 1 and phase 2, we had no idea that the Infinity War/Endgame was coming. Even when they announced it, we didn't know the level it was going to reach. Now it hit and passed. We're still in the build up phase. They just need to do the proper built up in the 3-4 films leading up to Secret Wars and Kang. The hysteria will be back again.
Then around Infinity War they said they were never doing that again. They'd probably just do smaller stories. They had no plan after Infinity War/Endgame and now it shows. Eternals was the only movie really on slate, and that was in the plans before. The plan they developed during been shot to hell (Captain Marvel/Spidey/BP).