The optimist will point out that the team is still only 1 game out of a playoff spot, and is not really out of the division race. There have been teams that have come back from middling starts before. Last season, the Dodgers were 33-32 at this point in the season before going 59-39 to clinch their division.
However, there are significant hurdles. Of their 95 remaining games, they have 24 against the Yankees and Rays, 13 against current division leaders (Twins, Dodgers, and Phillies), and 11 against teams in similar contention points as the Sox (Indians, Rockies, and Rangers). That leaves 60 games against inferior teams, some of whom will be in tank mode. If we assume they need to win 90 to clinch at least the second wild card, they have to play 0.589 ball the rest of the way. If they can play 0.600 against the lower division teams, that gives them 36 wins. Which means they would need to go 20-15 (0.571) against the upper half. Unfortunately, they are 6-11 against those better teams to date, and that's not counting their 2-4 record against Houston. Eventually, they'll have to beat the good teams.
Personally, I don't put too much credence on arguments that center around the team's "heart" or "spirit". I don't see them going to the plate and thinking "Well, I got a ring last season, so I'll just relax during this at bat, as this game is lost anyway". I don't see them somehow trying less hard or otherwise giving up. I do believe, however, the margin of success in baseball is always small and very difficult to sustain for any extended period. Injuries, regression, BABIP luck, aging, and roster turnover are all part of baseball life and contribute a lot more to a team's success or failure than "desire". It's still a talented roster, but the bullpen has issues that may not be easily fixable this season.