Incompetent isn't a broad term, it's specific, the question is are all children competent scholars? No, they're not, disadvantage implies that something has been taken away from or denied to badly performing students, that's not the case. Money and extra tutoring can't make dumb people smart so why not put more funding into psychological and aptitude testing of students then stream the competent kids into one system and the intellectually inferior into another. I've often expressed the view that all elite schools should be open to academic entry only with the state providing full scholarships to bright kids from poor familes, that way rich morons are kept out of the "old boy's" network and bright kids from poor suburbs are allowed social mobility.

Reply to Ian K
That is a very selective way to consider the notion of disproportion. The complete picture is that the 66 per cent of Australian students who attend government schools attract 78 per cent of public funding, while the 34 per cent of students attending non-government schools receive 22 per cent.