Hm. Zeality's position is basically thus:
My defense is mathematical; if there is a nonzero chance of a TD forming, given the universe exists for infinity, then it is inevitable that one will arise and devour all reality
I think we can safely say that the chance of a TD forming is nonzero, as we've seen it happen. Anything that happens has a chance of happening. Now, since the universe wasn't destroyed, we also know that there is a chance the TD will fail to devour all reality.
Assume that each dimension has it's own DBT. If this is the case, and DBT is then inextricably bound to its dimension, if the TD succeeds, it can only destroy it's own dimension, as other dimensions are out of its scope. However, since interdimensional travel is known to be possible in the Chrono series, and beings
can exit the DBT (see: the party) if there are an infinite set of possible universes, eventually a TD will arrise that can cross the dimensions. Luckily, it cannot possibly devour all time lines, we know this because if a TD had succeeded, Chrono Cross never would have happened.
If we assume that there is only one DBT, there is nothing to stop an infinite set of TD to wind up there, trying to devour reality. And if you have an infinite set of TDs setting out to accomplish something that they are all technically capable of, eventually one of them is going to do it. If this is the case, then Chrono Cross didn't happen. But it did, so we that obviously is not the case.