It's the natural consequence of a world where performance is difficult to measure, people are largely fungible, and next to nothing that you personally do will move the needle in whether your employer will be successful.
In that situation, why wouldn't you hire and promote your friends? All of the incentives are aligned for doing just that.
How much of it is "hiring friends" vs just hiring someone you have better information about? A lot of people interview exceptionally well but it's always something of a crapshoot how well they will do in the actual job. But for an internal candidate you should have a lot better information on how well they performed in other roles. You can have actual frank conversations with their managers/coworkers instead of getting BS references from people the candidate themselves chose for you to talk to.
Yeah, there are a few jobs I could recommend a specific person for because I know they are very good due to past experience. When opening come along though, they are usually not looking to change. But if they were... some would say I just recommended a friend, which happens to also be true.
And full-on nepotism is known to be bad. My bet is that blind recruits would perform just as well or better as the family and friends of the recruiting manager would if you'd run the experiment.
I think this is an overly cynical take. Reputation and VERIFIABLE track record are what is being selected for here. If a hiring manager views this as known for a candidate, there is basically nothing someone else can do to complete. The hiring process simply isn't sufficient to do this fact finding.
In my org, managers aren't really friends, but they do have trust. A strong recommendation is impossible to overturn.
Trust is really the main motivation in a lot of these situations. Imo, the value of “networking” in business is building trusting relationships with other people. I’ve gotten jobs by referrals from others, and helped other people get jobs via referrals. In those situations the referred candidate had an enormous advantage over the candidate off the street, but it’s not a system of buddies looking out for each other. It’s a system of people who’ve spent time establishing trust with each other.
It's the same reason why friends set up friends for dates. If you go "public" with apps, you can be setup with literally anyone. It often doesn't go well.
In that situation, why wouldn't you hire and promote your friends? All of the incentives are aligned for doing just that.