Tanking is a terrible strategy. It worked, (or might work I guess you would say since the Sox haven't won anything yet) in this case only because the Sox had two premium assets (Sale, Quintana) who could fetch a premium haul of guys who were all due to hit their primes within the same window. The odds of getting into that position again are small, so if the Sox don't win in this window, it could be a long time before it happens again.