Boras and Harper feel compelled to exceed the total value of the Stanton contract -- $325 million. The only way to get there is with a 10 year+ commitment. Teams are getting smarter, and not willing to risk a 10 year commitment where the player can opt out if he out performs the contract, but the team can never opt out. In retrospect, the Stanton contract (which is a 14 year deal with a player-opt out after 2020) was a bad deal. The Marlins wanted out of it, and now the Yankees would love to get out if it.
Agree that if Harper was willing to take a deal of 5 years or less, there would be a lot more suitors, and he would have options. FWIW, looking at Harper's body and how he has aged from 19 to 26, I don't think he is going to be one of the rare players that dominates deep into his 30s. There is no chance that I would risk the future of my franchise on a 10+ year contract for Harper.