Why don't you speak to your once best friend anymore?

Even as a teenager I had a “3 strikes and you’re out” rule for major assholery. Strike 1 was when the friend got a criminal acquaintance to physically threaten me for something that I didn’t do. Ironically it was friend themselves that did it and was so mad at themselves they needed someone to blame. Strike 2 was when friend publicly made fun of me for something I’d told them in confidence (luckily I’d fixed the thing I was ashamed of within a week, but then instead of enjoying that moment I had to go out of my way to make sure all our other friends knew so friend would drop it, which is what happened thankfully). Strike 3 was friend and I made plans for New Years 2000. This was more important to friend than it was to me because friend was still upset that some of our wider friend group had deserted us the previous New Year. Friend had even cried about that on my shoulder. New Year 2000 rolls around and I say we can do whatever you want but it has to be fairly close by because I have to work until 10:30. Friend ghosted me and I find out friend was already in another city at least an hour away. Friend had already driven there alone to spend New Year with someone else before I’d finished work and didn’t tell me. When I confronted friend the next day, the excuse was “I didn’t think you sounded excited enough about New Year, so I didn’t think you’d mind”. Even when I pointed out the hypocrisy of what had happened last year, friend just shrugged. I knew then that I’d just let the friendship slowly die, not contact them again, only speak for a short time if they called me etc. That tactic plus me moving to another time zone helped get that message through. With another close friend, I let contact go because friend was constantly complaining about family, work, education etc, but not doing anything proactive to improve their situation. At least some of the things could have been easily sorted in multiple ways. After a few years of this I think I said something along the lines of “You don’t have to take my advice but do something because it’s unlikely to change if you don’t.” But they never did, and although I feel a bit bad, it was too emotionally draining to listen to that constantly. I was young and didn’t think to recommend therapy. I think therapy would have helped them as I was unequipped to be an ersatz therapist.