Let's imagine that 20 years ago, you went to NUS and NTU to ask the lecturers the following question - "What is the mission of this university?". I believe that the most common reply would have been something like this: "To provide a good university education for Singaporeans."
But what if you asked the same question today? I believe that the most common reply would be something along the following lines - "To be one of the world's leading universities" or "To develop its global profile and reach".
In other words, the mission changed along the way.
The new goals are not "wrong" or "bad". They are all very worthy aspirations for an educational institution. But once again, if you personalise the question, you will see the implications. If these universities succeed in their goals to become world-class, then they will admit only world-class students (Singaporean, or otherwise). If they admit only world-class students, then many Singaporeans who are not necessarily stupid or incapable, but merely somewhat less than "world-class" will not have an opportunity to study locally.
Thus these Singaporeans will be forced to go overseas for their university education (if they can afford it), or otherwise simply quit school.
For those who do go overseas, there will be also an opportunity to experience life in another country. And these Singaporeans may (quite rightfully) feel grateful that here in a foreign country, there was a foreign university which accepted them, which gave them the chance to grow and gain their higher education - when their own country, Singapore, did not.
Why should we be surprised then, that some of these individuals will choose to stay on in those foreign countries? After all, Singapore failed to provide for them what these foreign countries were able, and willing, to provide.
Interestingly, as Singapore expands its vision of becoming an international medical hub, we may see an analogous situation occurring in the area of healthcare. The mission of healthcare providers in Singapore may shift over time. There will be increasing focus on attracting wealthy patients from other Asian countries. These healthcare providers may become more and more profit-oriented, and less and less focused on any notion about providing good, affiordable healthcare for Singaporeans.