They ghost because simply it’s easier for THEM – saves having to have a difficult, uncomfortable conversation. Far easier to just avoid it altogether. Certainly not an excuse though as who on earth likes having to give someone any bad news?
Of course it all depends on exactly why someone ghosts as well, but I believe in a large number of cases, it’s because they’ve met someone else, some of who simply are not thinking of the other person at all! They’re far too busy chasing the new love interest. If this doesn’t work out for whatever reasons, then this is when they’re most likely to make a reappearance! No way would I ever take someone back who has ghosted. Ever.