I still can't get notifications for this section of the forum... I even marked recently to get email notifications and that doesn't work either. But anyhow, I'm just seeing this now. My thoughts... yeah, it's very hurtful. We wonder forever what we did or said to make the other person go away. We also wonder if they're dead or very ill.
I think it should be a given that if you no longer want to talk to someone, they should at least be told. If a relationship, then "this just isn't working out and I'm going to pull away now" .... or if a friendship, then something like "I'm sorry, but we just don't seem to have much to talk about any longer." I do suspect that's much easier to type out like I just did than to actually say it to someone, though... but important all the same.
There's always that nagging thought about what we did wrong. And yes, I've been ghosted by a friend of 20+ years. Took 2 years to find out it was by death.