Yes, Kirk. All of that.
Trouble with a meritocracy is that one is at the mercy of someone's idea of how much merit one has. In other words "Your face has to fit".
Seniority works when it works. It can be ridiculous. It worked for me just because the company I worked for was expanding so fast the line was going down faster than they could fill the gap. You still had to tick the boxes.
Much as I hate to admit it (don't know why I hate to admit it, I'm obviously as irrational as some training departments..!) but FR seem as close as anyone to getting it right.