One example of a hobby-specific type ‘con’ that I’ve seen which does deal with massive crowds is the major fly-in airshows of Oshkosh Air Venture and Sun N Fun in Florida. They are week-long events where an entire, massive, airport turns every square foot of available space into some variation of parking, camping, exhibition, logistics, or retail.
Air Venture this year just had 590,000 unique visitors during the week. The entire city of Oshkosh turns into, more or less, AirVenture Town. All hotels are booked solid for the event probably 4-5 months before. Many families rent out their houses for the week or month (many people show up a week early and leave a week late) every year and use the proceeds to cover a few months’ bills. Those are almost all filled. Local colleges rent out the dorms, those are full. 500 acres of farmfield become a campground. That’s full. It’s a mile walk from the middle of the campground where the shuttles park down to the camping entrance to the event. It’s a huge ordeal, and everything fills up well in advance despite having a massive airfield and the only reason it is sustainable is its been going on for many decades in the same place with the same organization that has fine-tuned every aspect.
So that’s one example of a thing that’s more crazy than MAGfest and even that event basically ‘ends’ at 5pm each day other than there’s often an evening presentation at an open air theater by various significant people, and all the camping-related goings on.
Nerd cons are so unlike the professional conventions they aren’t even really the same sort of affair. PAX is even halfway to a normal con with the exhibition hall but only so much.
I do love me a normal professional con tho. Exhibiting is quite fun for me.