RENCI interview questions

I had a phone screen, followed by an onsite interview. For the onsite interview, I gave a presentation, followed by a panel interview and an interview with the hiring manager. The hiring manager appeared uninterested from the beginning. I did not hear back for weeks, after which I followed up and was informed that I was not selected. I have never had an experience where there was no response to an onsite hours long interview. I later learned that they hired internally for the role. That likely explains the disinterest and lack of follow up. Why waste other people's time when you have a candidate in mind already?