A team of replacement players will win 47.7 games per year. Call it 48.
The Red Sox have repeatedly stated that they try to win 95 games per year. I haven't heard that claim as often lately (more on that below).
The current market price is about 8 million per WAR. The Red Sox have a budget of about 200 million.
So if the Red Sox are relying soley on free agent talent, they can realistically acquire about 25 WAR. That gets them to 73 wins. That's a pretty humbling thought. The 2004 team was almost exclusively free agent talent and they won 98 games. Either the 2004 team massively overproduced compared to their projections, or baseball has radically changed in the past 10 years. So forget about targetting 95 wins. Let's try to target 92 wins instead.
If you want win the division, then you need to rely on home-grown players for the core of your team. Basically you need a minimum of 25 WAR out of your home grown players, and probably closer to 30. Guesstimating for inflation, a pre-arbitration player costs about a million per win, and an arbitration eligible player costs about a 3 million per win (see here).Assume half your core is pre-arb and the other half is arbitration eligible, and you're looking at 2 million per win.
So in order to get 92 wins on a budget of 200 million, we need to get 26 wins out of their home grown talent. That will use up 52 million of the budget. The remaining 148 million can be used to purchase an additional 18 wins.
Another way of driving this home is to compare Cole Hamels to Mookie Betts. The steamers projection for Hamels was 2.9 WAR. The Steamers on Betts was 2.6 WAR. Betts will make about 500k this season. Hamels will make about 22 million this year. As of right now, Hamels has accrued 1.2 WAR and Betts has accrued 1.0 WAR. Yet another way of putting it is that everyone who wanted to include Betts in a trade for Hamels was so far beyond wrong that even string theory be like "that's beyond wrong".
The point that I really want to make is that much of the hand-wringing over bad contracts and underperforming players is rearranging deck chairs on the Titanic (not that the Red Sox season is going to sink, they may get hot and sneak into a playoff spot). The only way to count on getting a legit contender is to build a powerful team through the draft. That means giving the kids a long leash because that's the only way to do it.