Hence the good ol' "We'll give you $5,000 for every engineer you refer to us...and there's no cap!"

At least good companies do this anyway.

Also, executive search recruiters kind-of do what you're describing. Exec leadership is a small-ish world, and the recruiting cycle for, say, a CTO can take months. However, there's a lot of commission on the other end of that. So recruiters basically act as brokers.

Meh. As someone who has moved around a lot this just sounds like friend nepotism. Based on this system I’d be a garbage tier developer since I don’t have friends in high places.

I much prefer the imperfect systems that at least pretend to be fair and objective-ish.