In the son-of-a-general instance, the son is born into those connections. But if you are able to associate yourself with high-level decision makers in a relevant low-status role, that can pay off.
I've done this twice, once as a marketing intern at a news startup where our CEO connected me with some decision-makers in the journalism industry (though I decided I didn't like the journalism industry), and again when I got my foot in the door as a customer support rep at a tech company to leverage my software development skills into a dev job with no relevant professional experience or education.