Not nearly as good a business as you might think I can assure you and we make a lot of effort to have a single customer - the delegate. There are no sponsor panels, exhibition booths etc that make events a lot more profitable. We have consciously decided to avoid these and focus on making the event as valuable for paid attendees as we possibly can.
Please don't forget we have a relatively high ticket price a finite number of places and very significant fixed and variable costs. This is not a software business.
We also try hard to incentivize early booking and offer discounts to encourage this so the average ticket price is significantly lower than $2,500. (Tickets cost $1,800 at the moment and we have sold almost 3/4 of them.