In my area, no privates really compete academically with public IB programs, the stats from one public school with 69% free and subsidised lunches for NM is outstanding. The IB programs don’t restrict via boundary either. The parents who choose privates are often not especially savvy, and might have fees paid by corporate in their relocation package. I think the catholic schools here really only exist in the numbers they do as a perceived inoculation against the predominant religion, certainly not for academics.