Myself, I think that may be a tad premature. Hillary's downward spiral may not have yet completed its trajectory, e.g., say if Hillary is indicted somewhere over the email thing. So many possibilities ... but yes, so little time really as well. But I would not totally exclude two or three months being enough time.
Or maybe they'll finally find the smoking gun of the Vince Foster murder. This will definitely sink her candidacy.
I don't know if you're being sarcastic, but Vince Foster committed suicide, he wasn't killed.