What made the world cup to be successful in Qatar was because Qatar has already set a standard that if anyone fails to hold will be punished, so their is no other choice than for visitors to just go to it. The next world cup will come well too based on the laws and standards of the host country.
Actually, all the countries hosting the world cup have had average success, I mean nothing extraordinary that exceeds other hosts who have hosted it, because everything has to be done according to FIFA standards, not the country's standards, such as the stadiums used, only hotels and other infrastructure that is different but nothing extraordinary including Qatar even though they are a rich country and can make more than what FIFA standardizes it will only reduce their profits, and there are still complaints from spectators and participating countries.