It's very true, and very natural. It's one reason why FAANG salaries have been getting so high.
If I change jobs, and find myself in a good situation, and need more head-count, I'm going to reach out to people I like that I've worked with before, see if they might be interested in a job change. I know I can work with them, know we'll build good stuff.
There's a constant drive in FAANG to hire more people, most teams have open headcounts. To the degree that it's extremely hard to build up that funnel of candidates. If my team has a head-count of 5, that realistically means I've got to find a bare minimum of 30-40 candidates to enter in to the pipeline from somewhere, to maybe get close to that target. That's a slightly optimistic conversion rate. Now scale that up across a company with thousands of teams that are hiring. Getting that pipeline filled on that scale is crazy. It's just one of many reasons why FAANG go all in on college hiring events.
I can almost 100% guarantee to get someone I've worked with in a FAANG co-worker through the interview pipeline and in to a job. They know their shit, they know what they're doing, and they know what the process is like.
It's because the DoJ Antitrust Division came down on them hard in 2010[1], and part of the settlement forbade the companies from engaging in that behavior again.
