It depends on how deficient you are, and how much of a show-stopper it is that you are deficient.
As with all things, there are two questions to ask when mulling over a solution to any deficiency:
1: What CAN you do? What are the sum of your actual options?
2: What will what you can do COST? Combine asset costs with opportunity costs.
In any analysis, "nothing" is something you can do. In any analysis, the cost of doing "nothing" is quantifiable. It should be weighed next to the cost of other possible courses of action, and if you come to the conclusion that "nothing" is the most cost-effective thing to be doing, then as a business you should be doing nothing.
These are very fundamental business concepts that I'm embarrassed for you that you aren't seeming to grasp in this environment
That said, the Red Sox are not doing nothing. What they are doing, is letting some prior investments mature, and staying flexible in the meantime. They're gambling on the youth program to replace some of the core players they've lost over the last few years -- especially Youkilis who was a HUGE loss for the team.
Without Youk, and with Beckett gone, no longterm options in RF or SS, and a catching situation in disarray, we don't have a core that's going to take us to the top no matter how we supplement it. Until that changes, assuming you can wave the Magic Wand Of Do Something, and make a 100 win team appear (you'd like to claim you're not doing this, but your attitude gives the lie to your words), is just delusional. There are too many fundamental problems with this team to call it anything else.