The problem with all of this is that we aren't trying to predict whether the guy will ever rob a bank again or assess the odds of him doing this one, which is where your logic works best-- we are trying to determine beyond a reasonable doubt that he did, in fact, rob this one.

That he robbed banks before is a fact, yes, but not one that puts him at the scene of this crime. Statistical likelihood is not a relevant fact in a criminal trial (but might be acceptable in a civil matter, where the standards are lower).