Hmm, this is tough yet simple. There are a lot of contributing factors to why they might not be reuniting.
Raz B and the whole “exposing” B2K thing. It has damaged the B2K brand. Fizz and Boog damaged that brand when they felt the need to speak out against Omarion in the beginning but I guess everybody wants to be heard?.
Despite what seems to be them having made amends, they probably don’t even really get along anymore. Their chemistry is important and because of the betrayals they’ve done to each other, it might not be there anymore.
Omarion is at the point where he’s focused on making a comeback with MMG, and Fizz is still trying with his music, so it’s probably just not on their agenda. Raz B is still in China, as well.
There might be legal things that prevent this, but there might not even be a real demand for it. I want to see it and I know others who do, but we might be it. They’re not gonna do it without it being a real opportunity to make money from it. They got kids/families now.
But I honestly don’t know what’s stopping them from at least recording one song together. But then again, Raz is a solo artist and I’m aware that Boog attempted a solo career; they’re not going to want to be in the group and not sing anymore.
I’ll make my official answer as:
They’re different people in different places of their life, who probably don’t even consider reuniting, but maybe someone will present them the opportunity and they’ll accept.
Just ask Fizz on twitter. Maybe he can pass the word along.