The way I see it, the thing that cost them was that every conceivably tradeable asset besides Vaz (and Verdugo and Bogaerts) became distressed in the weeks before the deadline, not any misplaced faith the team could make a run.
Eovaldi - hurt, lost velocity
JDM - hurt, then hit .167/.216/.267 from 6/27 to the deadline
Duran - hit .129/.169/.194 with a 46.3 K% from 7/7 to the deadline
Kiké - hurt
Cordero - hit .119/.213/.262 with a 51 K% from 7/8 to the deadline
Arroyo - hurt until 7/30, needed to cover 2B after Story injury
Hill - hurt
Wacha - hurt
Strahm - hurt
Dalbec - cratered after promising end to ‘21
Downs - hit .154/.171/.256 with a 51 K% before demoted on 7/29
Once all that happened, it made sense for Bloom to do what he did. Of course we don’t know the offers, but it would have been pointless to trade Eovaldi or JDM for more 35-40 FV prospects that need 40-man protection soon, because we’re already facing that roster crunch this winter. It’s also been reported that the Sox (and Guardians)
were in pretty heavily on Sean Murphy, so the incentive to trade Vázquez was higher.
I think a QO for JDM and a creative deal to keep Eovaldi around, with money and years depending on how well his fastball comes back this year, makes sense for everyone.