I think they are already taking benefits, they host the world cup games there are going to be many teams that come to these countries, and many fans from all over the world will come with them to watch the games, obviously, these people need hotels to stay there and foods to eat they will use the facilities from the host and they should pay money for it, this huge demand is enough for the hosts to help their business.
It is a fortune and an honor for every country to be chosen as the host of the World Cup.
Qatar had a very positive impact from being chosen as the host of the World Cup yesterday because Qatar now has a truly magnificent football stadium infrastructure apart from that there is the advantage of the Qatar national team having free tickets to compete in the World Cup plus several financial benefits as you have said.
I think FIFA should really choose a country that alternates every 4 years so that all countries in the world feel the positive impact and benefits after hosting the World Cup.