i was ghosted by a guy with whom i had one date, and we were in touch for a month after. he didn't reply to two of my messages, i wandered what happened to him for two weeks and then i didn't wander anymore.
i was not upset that he ghosted me, i just figured he liked someone else better because he was into this idea of shopping around, going on dates with different people at the same time (we were not in a relationship yet, so it is perfectly fine).
two months after ghosting me, he called me like six times at 7 am in the morning and left some desperate voicemail, crazy. one would think i ghosted him, not vice versa. i was not upset by him ghosting me but was upset with voicemail and didn't respond.

my old friend ghosted me recently, didn't respond to two of my messages, and that is perfectly fine. we were very good friends, but it was ages ago, and we really don't have any topics left, so yes, it should expire with gratitude for what was and without hard feelings.

i don't think that ghosting is a trait of narcissism necessarily, and i don't think it is cruel.
i did it multiple times on multiple people when additional explanations are redundant, serve no purpose, and nothing is left to be said.