I have a long history of not replying to messages. I now know at the grand old age of 42 that I am neurodiverse which explains a lot. Also have/had huge self esteem issues and a traumatic home life as a child (raised by a violent unmedicated undiagnosed neurodiverse parent whose maladaptive coping strategy was alcoholism) but working through these with a therapist.
I'm trying to make/keep friends as I don't have many. It was drummed into me from a young age that people are only interested in you for what they can get (see above) and we weren't allowed friends round. Said parent used to say horrendously wicked things about family members so I grew up understandably with a skewed view of people and the world.
I've let friendships go through my "I'm not worthy of friends so if I ignore them they'll go away which reaffirms my belief I'm no good" mentality. I'm thinking of contacting people now to apologise for my behaviour, to assure them it wasn't anything they'd done. I do not expect anything in return, at all.
Would it seem really bizarre to get a message out the blue from somebody who ghosted you years/months back though?
YABU - leave well be. I had my chance & blew it.
YANBU - send a message. It might make them feel better & could lead to a friendship.