Or they could do it like ADCC and have trials in different regions instead of every single state/country. They could have a bunch of trials - split Brazil and the US into multiple regions for example since we have so many more people training BJJ than some other regions. And hold 1 in Europe, 1 in Japan (and/or SE Asia), 1 in Australia, 1 in Canada, 1 in the Middle East etc, etc. It would make it easier for competitors to get sponsorship for the Mundial as well since you could say you "qualified" instead of simply paid $100 to register.
They could turn the Miami, NYC, Vegas, Asian, European CBJJ tournaments into qualifiers easily. Then it's just a matter of creating the others. They would end up making more money at these qualifiers because everyone would go if they had to win (or place) to qualify for the Mundial. IMO having qualifying tournaments would raise the overall level of the sport in the long run. At no other sport can you make it to the World Championships just by signing up.