I think if time and space are starting to become an issue, perhaps its time to start looking at dividing up the competition. Northern Hemisphere, Southern Hemisphere, ....or alternatively, by continent: Europe/Americas/Africa/Asia/Oceania.
After one gets past that stage there should be fewer able/eligible to attend Worlds, or it could be solely Teams. Might save on cost of travel every year for most, yet still arrive at a determination of who is World Champ, with everyone having been given an opportunity along the way.
Just a thought, unsure it fits with current dogma, seems money to participate is the qualifying criteria.