Teams knew Miami would not hand him away for nothing. That's why some did not claim him.
Stanton is NOT a salary dump: he just happens to play on a team that can't afford him.
His contract is much higher than his luxury tax number. That is something that appeals to only the teams in danger of paying those taxes going forward- the Sox included. He's owed $295M/10, but the luxury tax number is $25M. As much as I hate large and long contracts like this, especially for a player with an injury history, I'd sign this 28 year old to that contract this winter. It's a close call.
The thing that tips the balance to no for me, is the loss of young talent. That's why I mentioned the idea of trading one of the players we are not likely to keep down the road- Betts, JBJ or Bogey. I would not trade Betts or JBJ, so if Miami would listen to an offer centered around Bogey, I might try. The offer I suggested with Bogey is steep. It was an offer I think Miami would insist on, not one I would readily make.
Kimmi makes some great points. I'll add that trading for Stanton would certainly affect our ability to keep one or two from this list: Pom, Kimbrel, Sale, Bogey, Betts and JBJ, so not only would we lose top young talent, we'd lose some top vets later on..