It really is about who you know. If someone knows you're a good engineer (and their bosses think they're a good engineer), it opens a lot of interviews. A classmate of mine got me in to my first real dev/Java role, a backpacker I met in Malaysia recommended me a devops role I was at for three years in Chicago, and an old roommate got me my current gig in (which he sadly got laid off from a few weeks after I was hired 😰)