Maybe not the perfect analogy but...
The Red Sox have a huge revenue stream and decided to use it to sign a bunch of big-name vets to lengthy contracts. What are we supposed to do with this money, just let it sit there, they thought?
The U.S. has an enormous military and decides how to spend their weapons. What are we supposed to with all this destructive power, just let it sit there, they thought?
The Red Sox regretted some of those contracts. Carl Crawford was the biggest mistake. They ended up dumping Crawford on the Dodgers and absorbing a lot of his salary. They took a loss but at least they got out. Whoops, try again next year.
So I'm thinking Obama sees Iran as a 34 year-old future Hall of Famer who wants a $200 million dollar, 8-year deal. Intriguing, but the price isn't right.