Just a few thoughts:
For every team that basically starts from scratch like Atlanta did in 89 and has a brilliant run of success, there are five or more like the Royals who have been "rebuilding" for 20 years.
With the Sox it's not as simple as a pure baseball decision. In a two team market with a fan base that will not tolerate losing it gets a lot more complicated.
That said, I don't think you can burn the candle at both ends and succeed. Either the Sox have to go back to "going for it," or "start a logical rebuilding process." Rebuilding while contending hasn't worked out very well. The total number of wins under JR is right up there among the best of the AL in 32 years but the number of playoff spots in that time ranks below teams like Minnesota, Cleveland and Oakland.
Something is amiss.