Because it’s an organized crime syndicate and when you remove one top level, the next level of corruption moves up.
fifa makes its nut every four years. The other three years are all about maximizing that return. The Sport has long ago been relegated to second place, if that, in its thinking. FIFA is a media money scavenger and extorter using football as the means to the end. This is why FIFA want to run the World Cup every 2 years instead of 4, which of course pisses on the parade of the confederations. There is no honor amongst thieves. If FIFA cared about football they wouldn’t try to do something that would financially hammer the confederations.
FIFA is running the World Cup 2026 in a 3 nation setup - USA, Canada, Mexico. Mexico is the only nation in compliance with rule 28 - promotion and relegation in its pyramid - which is why it is involved … purely to permit FIFA to ignore its own rule. Cities are now going to battle to be a venue for the matches. Let’s see what scraps Mexico gets out of that deal. Its payoff is that it automatically qualifies for the finals and a small slice of the pie. From FIFA’s perspective the USA is the goose laying the golden eggs - big stadiums, big media, big money. Canada
… are probably involved out of pity and to keep them quiet - automatic qualification and a small slice of the pie as a bribe.