Why go through all that for nothing?

What is it with companies and recruiters that love to do a hundred and one rounds of interviews, all to just hire a candidate internally? What is in it for them? They are losing a lot of time having to review resumes (if they even do that), then having to schedule interviews with each candidate, which can take a lot depending on how many rounds they do. All to just disreagard all that work they did at the last moment just to not hire anybody, or just fill the position initially as they were intending since the first moment. I'm not even going to start discussing the amount of time they are making candidates waste. But focusing just on the company. Why would they do that whole arduous process if they weren't going to hire any candidate? Or why would they take a candidate to 5 rounds of interviews before disregarding his application? Like, in this story, why didn't they just reject him in the first or second round? If everything was okay with him during the first four rounds, why do a fifth? What changed in that last round? Let me guess… absolutely nothing. 

My theory is that most companies want to make it look as if they were growing and hiring more people to work there, when in reality they aren't. They do this by doing a certain number of interviews a month, or every quarter, but end up not hiring anybody. This makes it look like growth while actually not doing anything, just wasting people's time. This may be too far-fetched, but there is something weird about all this. There is no reason to think that this is normal, because it's not. Why would you hire a candidate 5 times? Why would you make them work for free to prove their value? And after all that. Why would you not hire them? I feel for this person. He deserved the job, and having a VP reject you over a 10-minute phone call while he's in his car and not listening to you is awful and unforgettable. That person should not be in that high position if he's going to behave that way.