I spent a lot of time studying and not networking in university; my family was (and is) mostly asocial (the prototypical hard working first generation immigrant), and no one really clued me in. I didn't get that important context until years later (thank you internet)
Living without a network in a foreign city, I managed to move from tiny 1000$/month contracts to consulting gigs then to a bigco. Every step was accomplished by meeting people, and solving problems, and then having them tell other people about me (and a blog article that weirdly went viral in the small space I was in). This might sound like an RPG, but it was not fun and the constant terror about missing rent was something I'm glad to have moved past. I don't recommend this at all, I'm way behind someone who got hired out of school by a friend at a BigCo.
As a result, I have a lot of sympathy for people without a network and I try to evaluate them fairly when I hire people. Sadly, without a prior relationship, it's hard for the evaluator and the evaluated to really know what to make of each other. It's always going to be easier to hire someone you know or someone a friend vouches for, as you will have the ability to have trust each other from the beginning.
So yeah. Tough problem. I don't have a solution.