I have often heard in the flights that in case of emergency first help yourself and then help others. The concept of self has always had a preference over the personhood of others. Having said that, the argument of the author seems to suffer from some fundamental flaws: The premise of his argument is based on an assumption that that work done by an individual is independent of any utility that she may derive from her work. It further assumes that utility derived by doing charity might substitute the utility which one may derive from one's work. Both the arguments are interconnected. Say, it is difficult to say how long would merely a charity derive A to suck up to a corporate job which she doesn't enjoy. This is an economic argument.
There are social and moral drawbacks too. If one does a work merely to benefit another and not because one enjoys it then society may be deprived of works of excellence and this drag may impede the development of society at large. Imagine if Einstein or Michelangelo, may have take up a corporate job to benefit others.
Third and the most important argument against this approach is moral. We all have autonomy to choose what we want to. It's certainly that one makes a choice to take up a high paying job, to benefit others. The fundamental idea behind exercising autonomous choice is to find ones' meaning of life. As the Greek philosophy goes on this, the purpose of life is to find ones' own destiny. I would place certitude and conviction to be of paramount importance in making ones' choice. If one's experience, culture and other influences lead to that certitude and conviction about ones' decision to take up a high paying job and do charity then that's fine, else one may find herself in a drag and thoroughly despicable situation, certainly sailing through against fulfilling ones' destiny.