A loss is a loss. If I opened my mouth to talk about the weather, they probably wouldn't listen to me now. Naturally, I'm trying to fill that void in other areas (online, at work, etc.). Is that unfinished business? Oh, it's just a set-up for a future adventure, whatever that may be.
In my probably unwanted, unasked-for opinion, sounds more like part of the process of reducing their influence to the minimum. That's not unfinished business. If there's no need for you to communicate and can let them go, considering that the conversation with them that many of us would love to have will never happen, doesn't seem like unfinished business.
I felt the same way when I started going to college and I'd hear people talking about the clubs they belonged to in high school the extracurricular activities they were involved in, the number of experiences that they all had that i never did. Looks exactly like what you describe about your friends that you departed from.
A few decades later now, looking back I realized two important things: (1) When I started taking a closer look at the realities of many of those people, not everything was great and fun. There were social pressures, family issues and a number of things that were not as great as they claimed their lives were, and (2) Most importantly, I now have a history with new friends, new experiences and pretty much an entire life that I now have after leaving.
How we move on and what we do really can help create an entire new wealth of good people and experiences.