I think you have that reversed. How can the statement "Bitcoin will surpass $5,000" be less probable than the statement "Bitcoin will surpass $5,000, due to X"?
I think you have that reversed.
I strongly suspect it's a joke about the conjunction fallacy.
The prediction that Bitcoin passes $5k, that there's a bitcoin ETF, and that both happen, are all interesting probabilities; the claim that the conjunction will happen (and specifically that the bitcoin ETF will be the primary cause of the Bitcoin price increase) seems like a conjunction fallacy prompt, that the additional detail is there to make it seem more credible rather than less. (Otherwise, you should use a conditional- if a bitcoin ETF exists, then the price will likely top $5k.)
It's time to look back to see what was predicted a year ago and how successfully it was.
But even more, it's time for the fresh predictions for the following year, 2014.