There is more to the story that we will never know.
I was in the hospital last February and 1 of my nurses who is also from Mississippi who said she was best friends with JC said the same thing about him not liking the North East.
This is such an important point. We forget that players are human, and that the motivation to sign somewhere is not always ENTIRELY about money and championships (though the money is a significant component, obviously). People keep family, location, and happiness in mind (in addition to the money and championships). I'm sure players also assess team culture, management, and unity, the so-called intangibles of any job.
Someone mentioned earlier in the thread with frustration how Seattle could keep Wilson, Chancellor, Bennett, Sherman, etc, and still have room to sign more. I thought that was a very interesting sentiment. I moved out to Seattle not too long ago and really love it here (I loved it in New England too). I have met a ton of people here in Seattle who have no other connection to Seattle besides getting a job here and relocating recently, and now they can't see themselves anywhere else. City is great, people are generally friendly, schools are good, and the weather is (shockingly) mild all around. Suburbs are nice for families. The Seahawks players are so integral into the culture of the city as a whole as well. They all seem thrilled and happy to be here, playing for a happy, jacked and pumped, cheer-leading coach. And yes, winning also helps. I can totally imagine most players who get offered generally fair to above average money for the top of their position will stay and those who want the big pay day leave.
New England's big draw is WINNING. Belichick himself says it can be difficult for players to play for him, and it's not for everybody. I'm sure there are skill players on other teams who are fantastic, at the top of their position, and may not excel in New England. If you're from the south, winters can be tough, and the culture can be a bit shocking. During my medical training in Boston, almost all of my colleagues were thrilled to be in such a great city, with such great hospitals. But the ones who were not happy (and still are extremely talented physicians) were almost universally from the South or California.
Elandon Roberts may end up as a better fit for the Patriots. Collins will likely continue to succeed. From Collin's perspective, I can totally imagine this: "I'm far from family, I don't really like living up here. I'll stay if I get Von Miller money, but otherwise, I think I might want to try some place else..."