Basically this. We just don’t have any information. All we know is that the game exists, and Inkling, Mario, and Link are confirmed.
Also, I’d credit it at least a bit to some of us getting older and more reasonable. Think about the Brawl days (the cloud theory, the Melee poll, the 35-character vs 48-character debate, etc) and the Sm4sh days (the shadow debates, “more boss characters”, the Tower of Smash, the character icon debate, the Sal theory, etc). I think people have just learned a lot from the last two (hell, it wasn’t even just Ridley! Speculation for both of those games was out of control in general, then Ridley speculation was just next level). This time, people aren’t quite seeing things that aren’t there just because they want to believe, at least not yet. If the Smash 5 trailer was shown for Brawl or Sm4sh, there would alread be heated debates about somebody finding Ridley and K Rool in the fire of the Smash logo, and Decidueye and Geno in the silhouettes.
tl;dr: the community’s consensus this go-round is “I’m hopeful...but I’m not falling for that **** again.”