I'm just not sure money alone would have gotten them a clear bullpen upgrade. We've seen what a mixed bag the deadline trades were and most of them required talent (albeit nothing too high-end). Dumpster dives are not a bad way to reinforce your bullpen, though they got lucky with Hughes (or not, since he's doing so poorly).
I think they really wanted another starter (better than Vargas or Smyly) but the trade prices were too high. And Arrieta didn't pull the chute until mid-August. That not only hurt the rotation but took Eflin out of the bullpen. And then Pivetta pitched himself out of it, but on paper, he could have/should have been better than another outside add.
Arguably they could have used another bat, maybe even two (for those who never wanted to see Rodriguez and Miller again) but they didn't give up on Franco until after the deadline. We have also missed Bruce and Quinn.
This is the basic disconnect regarding Kapler, however: if his bosses weren't really trying to make the playoffs they can't fire him for not making the playoffs.