what is the point of having massive HR departments if something as expected and frequent as university hiring can't go smoothly?

i managed to reach the interview round for a big 4 firm only for the interviewer to not show up for 4 hours from my time slot (i waited the entire time - took periodic screenshots for proof), HR to say "we'll reschedule your interview, this happened because of internal miscommunication" more than THREE months ago, and dip. until december they'd repeat the same. now they've ghosted. thanks, virtual hiring.

how is it the candidate's fault? found out this isn't rare by speaking to a few others from my network who i knew were interviewing for the same firm. for students whose lives can change completely based on the outcome of an opportunity that they came across due to sheer luck and could definitely make use of because of their hard work - this is so heartbreaking and demotivating.