Of course, the host country always benefits, although in the last World Cup reportedly the host suffered a loss, but when they become the host, they will automatically qualify and that is an advantage for them. Many countries are also competing to host the World Cup, that means they have calculated everything, including the benefits they can get when they get the trust to host.
I don't want to focus on that, what I want to see is the increase in the number of participants in the next World Cup will make the competition more interesting and I hope the countries that qualify there can provide many surprises.
Not that I deny that you are right about the general idea that many countries are competing to become the host of a World Cup, but do you really think that countries are competing?
I think it is all about politics and bribery. It has been like that forever when it comes to the FIFA giving their vote for a country to host the World Cup. Or rather the representatives of the FIFA for the various nations.
But yes the host has some advantage, which is quite natural as they have the whole country backing them and the people are everywhere inside and outside the stadium. But this is only valid for the football team itself, the people in countries that host World Cups are often times not better off financially, but maybe emotionally. Best example here is the last World Cup in Brazil that cost a shit ton of money while so many Brazilians live in poverty.