> It says that the probability is not zero. That is a very important distinction for some people

I'm not a mathematician, but I'm pretty sure it doesn't even say the probability of failed consensus must be nonzero. For example, the cantor set shows that it is possible to have a set with infinite elements, but zero length. That is equivalent to an infinite number of interleavings where consensus doesn't occur, but the probability of hitting any of them is zero.

Sure in real world systems, the probability would always be nonzero, but when it's still so close to zero, it practically doesn't matter. Which is why in the real world, people do build very reliable distributed systems out of unreliable components.