[Because not everyone is as inevitable as Maruki and Eren. Because not everyone meets their best friend in every reality. Because Kurusu isn't a god, capable of skipping through timelines and warping the very fabric of reality however he so chooses. Because Kurusu is not Eren, and so he's not Maruki, and so, they can only ever be separate, when everything ends, when there's only a wretched place like this left.

[That being said...]

You're meeting now. You get it, don't you? Think about it.

Even if this Kurusu is from a reality where you never met, he found you here. You found each other.

You and I...it's different with us, but...

Hythlodaeus followed us here too. If two people are meant to meet - if you believe that like I do, like we've talked about, then...

[It makes sense. He isn't placating Maruki. He wouldn't.]

This is where the story starts. He still needed you. He found you.