I can't agree that BB was looking at a rebuild. I think he erred in his assessment of Brady. He thought Brady was losing it.
If anything, Belichick erred also in his estimation of how much Brady or Scarnecchia helped with the OL in previous years. BB thought you could throw practically anyone out there and you could coach them up. Last year taught us that Korey Cunningham, Marshall Newhouse and Ted Karras were not as capable as those they were replacing. For many years, Dante and Brady fooled us into thinking you can get by with Mike Compton, Russ Hochstein, Donald Thomas, Trent Brown, etc.
My thought is that with an in-tact OL Brady and the team would have been better than they were the prior year.
Brady's salary was largely irrelevant in all this because we really gained nothing by not having him here. It's not like we used up the cap space with new FAs due to his absence (I'm not criticizing BB for that, BTW).