I've been a technical interviewer. The process sucks from our side as well. I'm in a medium sized tech company.

The generic job description thing is due to HR. The job description is something like two pages, and we get to contribute two sentences in the middle. We're trying to build a more diverse team, so we've been able to convince HR to remove some of the "candidate must have 20 years of Rust experience" crap.

I'm not sure if we're offenders in the never ending interview process. We typically have two interview sessions. In a few cases we've asked seniors to come back for a tie-breaker.

One of the problems interviewers face is that it's really hard to detect competence in an interview. In a couple of cases we've had people flub coding questions, but they seem good otherwise. In other cases we've hired juniors that did well on coding questions that aren't great employees - they suffer confidence/motivation issues.

It's frustrating because I haven't been trained to interview people. I don't think our process is particularly good (or bad), but I don't know how to make it better. Most of what I read about it online is contradictory. We've hired some amazing developers, but we've also hired some people who don't contribute very well.