You have been spot on, all morning, and I don't disagree, here, but I do think the budget, especially if Bloom was told to stay $6-10M under the tax line, played a major role is what happened.
We needed to build up the pen, badly. Nobody disputes that. One could argue, we could have used one more Chris Martin, but I think Bloom did a fine job maximizing his return on investments made to the pen. Not signing Martin or Jansen, so we could add another SP'er would not have been a good choice.
We needed to replace some offense and fill the SS position, while also starring down the fact that our OF was one of the worst in MLB, last year and in my 50 years of being a Sox fan. He had to spend there. One could argue, he should have spent more on JT and Duvall. so we'd have them for more than just one year. It was a huge but winning roll of the dice to not spend on catching. (I recall some posters wanting us to go big an a FA catcher.) He spent pretty big on the OF with Yoshida and Duvall, and it could easily and rightfully be argued that the money spent on Yoshida (and Kike from the summer extension) to be spent on pitching. That looks to be on Bloom, but there was talk that the Sox system had been super high on Yoshida for years, so maybe signing him was more of a group choice than Bloom insisting on it. Still, he's the the guy making the choices, so that has to be a valid criticism. Bloom did not spend much on 1B/DH. The JT signing was masterful, except in length. The dice roll on Casas worked, too. The dice roll on Kike & Co. at SS was perhaps almost as big a blunder as neglecting the rotation.
The fact is, he spent on the pen, the OF, DH/1B and was mostly a success in those areas, as a whole. Robbing Peter to pay Paul was something most of us felt and still feel he should have done, and that's on him.
I'm not arguing Bloom having $6-10M more would have solved the rotation problem, but it could have helped. (Wacha cost less. Eflin or Nate over Kluber would fit, and so on...)
Bloom needed to do more for the rotation than he did, There is no sugar coating that. The 8-9 guys we had looked okay, but okay rotations rarely reach glory.