Sure, when you go to networking events, you aren't certain you are going to get a job from the folks you meet.
What you are doing is increasing your luck surface area. Hiring is not an entirely rational process, but if someone doesn't know you exist, they won't hire you (how could they?).
From there, it follows that meeting someone and letting them know you exist increases the chances (however small) that they can and will assist you on your career path. And a networking opportunity, where you meet someone face to face (and can meet them repeatedly) is a far better way to let someone know you exist than sending them your resume.
There are other ways to raise your profile that don't involve networking events and you can argue that they are better, but that's a cost-benefit analysis you should consider.