It's not so much that as it is that it all fits together too snugly.
If Ken and Incineroar are all that remains, then the box could look something like this.
View attachment 164346
This fits quite snugly on both sides of the box. Sure, there could be more. But either one side would be uneven, or it would be completely different. If there were more than two on the visible side, why not just make K.Rool the last one in the placeholder?
The following Twitter thread explains things nicely as well.
@Swamp Sensei originally posted this earlier.
https://twitter.com/ConnorEatsPants/status/1040744991176486912?s=19
This being the final roster also confirms what Sakurai implied.
The total amount of stages on base roster for Smash Ultimate is 103. Neither Isabelle, Incineroar or Ken would require a new stage, which would now make three connections that corroborate 2 more Newcomers.
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Now, this isn't directed at you
Luigi The President
, but I want to say this, and I really don't want to be that guy but I'm gonna say it.
You guys call this Smash speculation? Speculation is based on taking the information and dissecting it, analyzing it, and coming to a conclusion. The people saying it's "just a boxart" are literally coming to that conclusion by ignoring
ALL OF THE INFORMATION that seemingly stacks up.
That's not speculation. That's willful ignorance. Sorry, but that's the truth.
I personally want there to be more characters waiting for us. But the information we've been given seems to piece together so snugly that it just makes too much sense.
Again, everybody needs to take a deep breath and think about it.