How hard did they try? What were the offers from the Sox that X turned down? What offer would you have made to keep him from free agency? Do you think Boras had no idea that he'd get something around what he got as an FA and it was just lucky that he did?
I don't think even Scott Boras envisioned a year ago that Xander Bogaerts would get an 11-year, $280 million contract after the 2022 season. Not even close. Again, while the Sox were far off the Padres' offer, there were like three other teams who were "in the neighborhood". And by that I mean, they were still like $80 million short of what SD offered.
What I think happened was that the market until a couple of days ago was about 7/200, and when SD took two huge swings and missed on both, they knew they needed to just blow people out of the water, and they did with the offer to Bogaerts.
So what would have been enough for Boston to keep Xander BEFORE it ever got to free agency? Not sure, obviously, but the Sox didn't appear close to 7/200, and I bet Boras would have strongly advised Xander to not take anything much less than that because he had an idea where the market might be.
Again though....even Boras had no idea (I don't think) that SD would give them THAT kind of deal.