I think one could argue that the following two premises cannot be true at the same time:
- An infinite number of parallel universes exist, where anything that is possible will happen.
- It's possible to traverse from one universe to another.
We can show that both cannot be true simultaneously with a Reductio ad Adsurdem.
Simply put, if it's possible for someone, within a civilization advanced enough to produce the technology, open up such a "trans-universe portal" into my office right now, it will, because if it's possible, it therefore will happen.
Alright, nothing is happening.
So, either #1 or #2 is false. I'm willing to bet it's #2.
Of course, since the scope of my knowledge (and humanity's) is limited, there could be a number of factors that play a role. Maybe there's just a lot of universes, instead of infinity. Maybe the minimum time required per universe for an advanced enough species to invent the technology hasn't been reached yet.
Interestingly enough, while I "showed" that something is not possible, what I haven't done is demonstrated that something else is more likely true. Yes, creationists, that's you I'm glaring at.