It's not as simple as either one of the premises, yours or his, of course.
Teacher salary will attract better teachers...somewhat.
But can better teachers get a class of North Philly kids admitted to Princeton?
The salaries at many private schools are not a lot more than private counterparts and even worse in suburbs of big cities, but the students perform better.
Wealthier students will perform better depends on family, safety, nutrition, and a gajillion other reasons.
So the social engineering isn't as easy as pay teachers more and get better student results. Better pay only helps so much.