I too didn't feel ghosting a long term friend was right. I felt I owed her an explanation. This is my experience
We met when I was doing a masters in a western US state, after moving there from the UK just after finishing my undergrad. She was doing an undergrad degree and was slightly younger than me. We saw each other through marriage (both), divorce (hers), infertility (mine), adopting children (me) failed relationships (hers), and sobriety (mine.)
Point is, in the first ten to fifteen years I felt, and feel looking back, we supported each other mutually. When she divorced, I spent a huge amount of time with her. I celebrated as she got put and formed new friendship groups, got excited about a past time gain she'd given up due to her marriage. I felt she celebrated my sucesses and supported me as well.
Over the years, I realised our dynamic was changing. She was very interested in my failures, not any success. She mocked my accent, claiming I mispronounced words when I used a British accent. She spoke constantly about how bad the religion I practice is. It was subtle, but there.
Finally, after 25 years I realised it had become toxic. I stopped drinking and she reacted in hindsight badly. I wasn't the friend with problems she could commiserate with, and in some ways feel superior too. She berated me it I did activities without her, but left me out. So was increasingly rude when she did come out; I asked her to come out to a play with a group.of friends for example. She arrived late, spilt beer over me and complained about the seat we had kept for her. She broke her ankle and I went over every morning for six weeks and cleaned her cats litter trays as she couldn''t kneel. I broke my ankle and she offered to do nothing.
I can't quite explain it, it just slowly happened and I didn't notice. Until I did.
I just sat down one day and realised I dreaded her calls, we had nothing in common anymore, she expected 100% from.me but gave me nothing back. Friendship is never even, and shouldn't be transactional, it isn't that I expect I give you an hour, you give me one back, but this was just off. We weren't having conversations anymore, just her calling me to tell me complaints. When we did made plans, which she frequently cancelled, it almost always turned out if we did meet, she wanted help moving something (a trip to a garden center turned into me moving bags of compost for her.)
So, I set up a time and to meet with her, She arrived almost an hour late, which was fairly normal, with little apology.
I ended the friendship. I told her that while we had had good times, and had been supportive of each other, in truth that hadn't been the case in the last few years. I explained we had grown apart and I felt it was time to acknowledge that and move on. She demanded why. I said we had nothing in common anymore. We really hadn't had a good conversation is months if not years, that we both were more comfortable spending time with other friends. That neither of us were bad, we had just moved on.
She got irrate and left, turning to tell me I was an awful human being and if this was sobriety I should drink again.
She posted a long tirade on social media about being stabbed in the back.by her best friend
Afterwards, I ran into mutual friends several.times. I would never bring her up, but to a person they did. And they would say some version of you helped her so much and she treated you like dirt.
Now, almost ten years later, I'm glad I spoke to her face to face. I'm.glad I didn't ghost her. It was one of the most painful things I've done, but I felt I acted with integrity. She doesn't I would guess. I wish her well.