It might be that there is another planet, or it might be that our understanding of the universe is incomplete. It seems to me that the information that there is something out there that isn't covered by our predictions is quite useful for directing science.
Absolutely not! That would be irrelevant, out of scope, and completely unreasonable.
That said, if you're going to opine that you have a better model, you might be best advised to bring data that demonstrates it.
[citation needed]
I don't know about predicting the mortgage crisis but if you assume humans are human in all sorts of awful ways then you should stick to systems which are simple robust and hard to screw up and time tested rather then the opaque mystery content derivatives that fueled the mortgage bubble. This may have prevented it rather than predicted it.
The prediction thing is tricky as in the joke "The stock market has forecast nine of the last five recessions." There are always people predicting things will go wrong but how do you filter which to take notice of?
Check out Misbehaving by Richard Thaler for the entertaining details.
Synopsis: The notes below are our attempt to re-develop economic theory from scratch, namely starting with the axiom that individuals optimize what happens to them over time, not what happens to them on average in a collection of parallel worlds. The latter, surprisingly, is the starting point of the currently dominant form of economic theory.
[1]https://twitter.com/ole_b_peters/status/1041252157956280321