At a guess (and completely a guess), legal compliance. Insurance laws can vary widely, and subtly state-by-state. A licensed broker will understand the relevant

At a guess (and completely a guess), legal compliance. Insurance laws can vary widely, and subtly state-by-state. A licensed broker will understand the relevant intricacies and be able to sell you a policy that is compliant with them. If you buy a policy from an unlicensed broker, and it turns out not to be in compliance, the carrier probably isn't obligated to pay out, whether you're paid up on your premiums or not. The carrier doesn't want to be at fault for not having to pay out, so they offload that onto the broker, and "protect" the consumer (really, though, themselves) with a licensure regime. Insurance companies, being in the business of managing and mitigating risk, have all kinds of meticulous i-dotting and t-crossing procedure and regulation. This is — again, at a guess — just another example of that.