“Davening properly is more important than anything a girl will learn in school”
That seems like just the kind of belief that would come from not learning anything in shcool.
Are you implying that anyone not davening shemona esrei for an hour is not dovening properly? If so, fine. But if one can daven properly in less time, and such a long tefilla is merely a hiddur or personal preference (assuming its not counterproductive in itself), then yes, there is good reason to think that other things might be more important.