But it might also be the case that costs go higher in the case of multiple nations hosting it.
Costs may go up, but it is mostly for the fans and not for the organizers. Look at the FIFA World Cup of 2026. A total of 3 countries are hosting it - United States, Canada and Mexico. For the hosting nations, this arrangement is somewhat beneficial, because the matches are spread out across different localities and no new facilities need to be created. But for the fans, it is going to be a nightmare. They need to frequently travel from one country to another, if they want to attend all the matches of their team. Visa issues are there, and then there is a need to travel thousands or even tens of thousands of kilometers across different countries.
In fact, do you think that the next World Cup Qatar will be able to overcome the historic World Cup and organize a better one. But I think that since three countries will host the World Cup together, we will be able to enjoy something great from Qatar.