This idea has been tried before and has failed many times. It is a hopeful, but the execution usually suffers due to the economy and people being unprepared to handle such a sudden boom in labor and economy. The work that is needed will surpass any potential profits and the notoriety of the Olympics will be overshadowed quickly after their commencement, leaving the town in a fiscally worse situation.
Pretty much every city or country that hosts the Olympics loses money, and often they end up with a bunch of stadiums and other buildings that are under utilized after the games. Take Greece for example, which is still paying off the debt from the last time it hosted. Local businesses may make a bunch of money, but not the city itself.
Rio bit off way more than it could chew in order to be the country hosting the Olympics. It still has sewage running into the waterways, crime is still at an all time high. I've never heard of athletes being held up ...until now. Many tickets are still available for purchase. They promised to have the homes in the country hooked up to a sewage system by the time the Olympics came around but have failed in doing this miserably. It is going to be a disaster for the athletes and I hope no one comes down with the zika virus.
The Olympics will be a great source of revenue for Rio as tourists flock to the summer games. Unfortunately, this influx of revenue will be temporary, and the residents of Rio will be left with what they had before the games. Hopefully, Rio can use the facilities built for other purposes and work on the living conditions of its residents after the Olympics.