My ''audit'' happened organically recently after some major life changes.
I had a few really difficult years with major health issues (and work issues as a result) and was the victim of an assault by a male acquaintance.
I thankfully had trauma therapy which helped immensely and made me realise that I was still a people-pleaser too and that I had to build better boundaries.
I sold my home and moved to a new town for a fresh start and also got a new job. I also cut out some toxic relatives out of my life.
At that point a lot of ''friends'' faded away.
One because she was used to feel superior in my presence (as I was always the struggling one...) but could not cope with me when I started asserting my boundaries and do better in life.
Others I let drift away because I realised they were just fair weather acquaintances and we no longer had anything in common.
I have since made a couple of new friends and make sure I have healthy boundaries in place form the start. I have also kept existing ones, people who have shown me that they genuinely are happy for me to be doing better.
My point is it is often normal for people to fade away as your outlook on life and your priorities change.
Traumatic events will also often show you who your real friends are.
As you can see from some of the comments you have had so far, some people will just cling to old friendships at all cost out of fear of being alone or because it is easier than to risk ''upsetting'' anyone....
Friendships like any relationships are not always meant to last forever.
My view is that the right people will come in your life at the right time. Meaning if you find yourself letting friendship drift/go because they have run their course, they will be replaced by new ones that better fit your current life.