I just don't understand the thought process. Did they really think that Joe Biden was going to run away with the nomination three months before the first caucus? Do they hate Pete that much? Pete is the only variable of this equation that has changed since last spring. Deval Patrick is exactly like Pete if he weren't a war veteran and a gay white guy from the rust belt. Patrick has less mass appeal than I would if I ran for president.
i can't pretend to know what patrick is thinking, but my guess would be that he assumed that somone, or several someones, from amongst the younger cohort of candidates would have emerged to topple, or at least challenge, biden's spot as the leader by now.
re. buttigieg, i'd guess that patrick sees him as someone that would need a set of very strange circumstances to secure the nomination and should he somehow do that, someone who would be a dangerously weak candidate in the general.