Applied online, contacted by recruiter, did a 1st round with engineer director, then nothing. Not even a rejection. Why is it so hard for companies to treat candidates like people?

Process took about 3 weeks. First was a call with the external recruiter, followed by a call with the internal recruiter, then an interview with the engineering manager for the team for which I was interviewing. He asked a series of intermediate React and API -centric questions. And then ended the interview with some behavioral questions and some time for me to ask him questions. After that I had the option to participate in either two one hour virtual coding interviews or do a 4-hour take home. I chose the take home due to my busy schedule during work hours. The take home was a React app with a Flask backend that I had to build upon in a series of increasingly challenging tasks. After I passed the take home, there was one hour follow up with two senior engineers who interactively reviewed the code with me. This was followed with a 30 minute checkin with the original Engineering Manager I had met where he asked me a few more in depth behavioral questions geared toward collaboration and conflict resolution. The final meeting was with the original internal recruiter who asked for feedback about the process and then told me I would be receiving an offer. Overall - it was a fantastic experience. Everyone was kind, communicative, and super helpful. What I appreciated most is that they never once left me hanging. They were extremely on top of their communications.