The bad thing about the 2026 world cup and even previous world cups is getting auto qualification when they host the world cup. I mean when they host the world cup they get some advantages, for example, they will have more visitors for their country and it helps the country financially while getting an auto qualification is not necessary and they should get qualified like other teams.
If my country is hosting the World Cup and it failed to qualify for the competition, I will never go to the stadium to watch any game. The majority of people that go to watch these games are from the host country. Apart from the supporters club of most countries, the stadium will be empty without the citizens of the host country. For the competition to be entertaining and profitable, host nations should be given automatic qualification tickets. Don't also forget that these host nations will also spend millions of dollars on football facilities, infrastructures, personnel, and other essential services. We shouldn't assume that it is FIFA that finances all the projects, so they need to be compensated with automatic qualification.
If you think that if locals ignore stadium attendance that will change something, then you have never experienced any hosting a world cup

Locals dont go to stadium in general. Foreigners are the one who fill stadium most. Country does not earn much from selling tickets. They earn from selling intellectual rights to air event (plus earn huge from advertising contracts). Locals rent their apartments for sky rocketed prices. Country get a huge recognition and popularity. Country earns from tourists not only during world cup. Business receives new and additional investments. But all those facilities, infrastructures, stadiums in the end are waste of money. Spending money on building them never pays off.
How magnificent the next World Cup will be will depend entirely on the FIFA authorities. However, the host countries will have great responsibilities. But I think countries may not be able to organize like Qatar. Because Qatar spent a lot of money on the World Cup.