Its actually the opposite. It was indeed designed for the expats, diplomatic corp and those who are rich enough to live in exotic locations but want their children to accepted in the elite schools of the west and a common acceptable standard was required. IB is also more expensive as there are additional fees and a mandatory component requires an overseas trip or internship that also cost money if your family is not connected
By the way the global rating is misleading as schools in Northern Hemisphere and the West take the exams in May. Very few countries take it in November. The ratings are therefore based on which exams you took.
IB however is of much higher standard in all disciplines and everyone should be encouraged to take it. Generally it is equivalent to 1st year in many Universities. In addition provisional admission to Ivy League and Oxbridge via IB provisional scores is also faster albeit it most cases they are conditional.
More importantly the IB development component and approach makes sure that you do not end up like PAP educated zombies who are good and compliant but can't think for themselves. As students have to sit for same identical paper in which ever country they are in, the PAP has no say whatsoever.
And the irony is that the IB was originally designed for poor students around the world who couldn't afford going the traditional A level route. Only in Singapore does the reverse happen. Which also explains why the rich Singapore IB students top the IB exam rankings around the world every year, even moreso than A levels (for which RJC is internationally well known for ranking #1 in having the highest % of its students entering the elite Ivy League Universities, among all high schools worldwide... coz elite rich parents of RJC kids can afford overseas Ivy League Universities, combined with the Asian education kiasuism culture where Singapore already tops the world in education rankings like PISA & TIMSS, of which RJC is already the elite of the elite in Singapore).