The word "rebuilding" is about setting customer expectations. If a team is going to go young - they are going to lose - a lot. But there is purpose there - especially if the kids have some talent. I don't think the Sox get to that point - at all.
1. Betts, Bogaerts, Benintendi, Devers will all be 28 or younger. Yes, extensions for Betts and Bogaerts will be expensive (and yes that decision is fair game). But really it is a matter of the payroll and tax Henry wants to carry. This team can probably work with 2 years - reset as a pattern. They might not want to do that - but that is because of ownership's priorities.
2. While the Red Sox could slip in 2020 for some of the reasons cited above - there is almost no chance that Betts or Bogaerts, under contract for 4-5 years would not be a pretty darn tradeable contract (Betts in particular).
3. The prospect inventory is not great right now - that is a challenge for the development guys. Teams cannot push chips around in the amateur market like they used to (ironically this hurts Tampa much more than Boston) ... but do the Red Sox have the scouts and development guys to find those sorts of 2-sport kids and whatnot who blossom and such. This part worries me also.
4. The window of opportunity for this team is 3 years for sure - but it could be longer. It depends on whether ownership wants to choose to do it - and pay the freight. The team is chock full of young, good players - with more than enough financial wherewithall to keep. It is always tempting to treat the tax as a hard cap - because ownership might ... instead of questioning that premise.