The team is one the youngest in the NFL (#3 in 2018). Among their six CB's would be Jones, Jackson, Crossen and Dawson. And you want to get rid of McCourty because the group isn't YOUNG enough?
I think you may have misunderstood my post. The very first thing that I stated was that: "I'd like to see Jason back for another year." Depending on Dawson's development (a mystery man so far), and on
whether or not Jones is back (I could see Lions or Dolphins making a strong push for him, for example), my suggestion was that a contract offer to Jason might be a little more likely. I don't know if the team will decide that the youngsters are sufficient, or if they'll prefer the veteran leadership and steady play Jason brings. Re-signing Jason is my preference, which is why I said that I'd like to keep them all. I never suggested we should get younger just to get younger.
Oh, and while we're discussing the young corners, Crossen was a draft favorite of mine, but he hasn't set the world on fire on defense. He's been good on special teams, and I'm still positive regarding his continued development, but I don't think he's reliable depth just yet. If Jones leaves in FA, and Dawson and Crossen don't take the next step, then depth looks poor.
The second part of my comment was unclear -- I was thinking of the secondary in general, not just CB, when I mentioned a need for understudies. Chung and D. McCourty will probably start another 1 - 3 years, but they're both likely on the back end of their careers. Perhaps Melifonwu steps up and becomes a more consistent player. Perhaps not. But as much as I like Harmon, he doesn't play quite the same role as Chung or McCourty. I would expect the Patriots to add a safety in the draft somewhere in the top 100 picks.