A large fan convention looks like a ticketed event and functions like a marketplace. Admission covers only part of the cost, and the structure of the weekend is designed around the revenue that follows people through the doors.
The venue is the dominant fixed cost
Convention centers are rented for the setup, event and teardown days, with charges for power, internet, cleaning and security that scale with the size of the floor.
Those costs are committed a year or more ahead, before anyone knows attendance, which makes the event a substantial bet on demand that has not yet appeared.
Because the commitment is fixed, additional attendees are close to pure contribution once the threshold is passed, and falling short is severe rather than merely disappointing.
Exhibitor space is the primary revenue line
Vendors, artists and publishers pay for floor space, and that income frequently exceeds what admission produces. The organizer is effectively selling access to a gathered audience.
Pricing varies by location on the floor, with corner and entrance positions commanding more, in the same way retail rents vary by footfall.
Artist areas are usually priced lower than commercial booths, because a strong creator presence is what makes the floor worth walking and therefore what the larger exhibitors are paying for.
Guest appearances are their own economy
Guests are paid appearance fees plus travel, and the cost is recovered through paid signings and photo sessions rather than through the ticket price.
That arrangement lets organizers book more guests than admission revenue would support, since each one carries their own means of paying for the booking.
It also explains why an autograph carries a separate charge at an event a fan has already paid to enter, which is a frequent source of confusion.
Panels serve promotion rather than income
Programming rooms generate no direct revenue, and large panels are expensive in space and staffing. They exist because they are the reason people commit to a specific weekend.
Studios and publishers participate to reach an engaged audience directly, and increasingly to generate footage that circulates far beyond the room.
The panel is therefore a marketing exchange, with the convention supplying an audience and the participant supplying a reason to attend.
Crowding is a safety constraint, not a preference
Capacity limits on halls, queue management and timed entry are imposed by fire codes and venue agreements rather than chosen by organizers.
Those limits interact badly with unpredictable demand, since a panel's popularity is only known once the line has formed.
Most operational complaints at conventions trace back to this mismatch between a fixed building and an audience whose distribution across it cannot be forecast.