Employment is like dating, there are frequently things that happen outside of the process that impact the process and there are often reasons to avoid direct rejection even if the reasons are different.
Jobs might be posted and then the position itself is made redundant during the interviews, so they are no longer hiring. Or they liked your interview, but want to offer you something else and have to do the HR circus to make that offer happen and the whole thing falls through. Or during the interviews they decide they want to change the position into something else. Orbthey are incompetent and HR forgot to follow up on the job offer. I have seen all of these happen!
Then there is the all too common scenario of finding out the candidate is a woman or a minority and sone jerk killing the process. Can’t admit that so they ghost. They might have a valid reason not to hire, but don’t want to be sued for giving a reason. They might also have posted the thing to meet a requirement although they know who they were going to hire from the start. I have seen all of those as well.
Or they don’t want to tell a candidate they didn’t meet the position for fear of violence. This is likely being over cautious and not specific to the applicant!
Or the applicant reminded an interviewer of someone they don’t like.
These often line up with dating because they are all things that have no real specific explanation that can be given as what the csndidate can even do to change. Knowing they are possible won’t really impact how the interview/dating should go in the future either, because they are all external to the interview or dating process.
So the best way is to come to terms with the fact that there is likely to be someone who is a better fit, or the position wasn’t really stable, or you didn’t want to work or date them anyway if they didn’t follow up.