Nobody planned it this way. Marketing was hired, or an agency was, to bring enquiries. Sales was there to close them. Each does its own job and reports its own number. What no one set up is the agreement in the middle: what counts as a lead, who picks it up, how soon, and what happens when it goes cold. In most owner-led businesses that agreement lives in your head, and it only works when you are in the room.
Why it persists. Each team is measured on its own number, so each team works to it. Alignment has no owner: it is not marketing's job and it is not sales' job, and the person who could own it, the owner, is the busiest person in the business. Hiring another salesperson or changing the agency always looks more like action than writing down an agreement between two teams that already exist.
If it stays unresolved. The business keeps paying twice, once for the enquiry and again for the salesperson's time, and the two purchases never quite meet. Every new campaign restarts the same argument, and the owner remains the only place where the two halves of the funnel connect.