One understated fact about all those winning seasons the Sox had starting around 2003 was the fact that we let some very productive players bolt, before they reached their declining years. Some still hurt like hell, and a few we wish we never let go- like Beltre and Lester, but for the vast majority, we made the right choice. Even the Damon departure worked out okay for us. When Ellsbury bolted, many were pissed off, but wow- nice job, right? Many hated letting Beni go, and he did have a couple good seasons afterwards, but right now, he has one of MLB's worth fWARs among everyday players.
We made plenty of mistakes on some, but we did well letting many go, when the time was right, just right or nearly right. Letting Betts go, was a big mistake, but he did say he wanted to be a FA. DD acted on that, and the rest is history.