Minimum wage here is $19.49/hour. What you're suggesting is:

* Pay $739 weekly * Provide all food, plus cook for them * Provide their own room in the accommodation * Cover the costs of all their utilities (water, gas, electricity) * Take them on all holidays, etc

I know your suggestion means well but it would mean Au Pairs cease to exist. It's lose-lose. The Au Pairs here aren't coming for a poor nation to earn money from back home, they're coming over for cultural exchange. For example, my sisters Au Pair was from a wealthy German family. Maybe it's different in other countries, the article talks about Columbian Au Pairs.