I think you need to be very clear about what you are talking about here, as others have identified. Ground school tuition is NOT in my book connected with what a flying instructor does at all. However, I cannot see how a flying instructor can begin to go flying with a student without a thorough flight exercise brief (and debrief).
A flying instructor should do the briefs and debriefs, but they pre-suppose a certain level of knowledge.
It was envisaged that the ground school/technical knowledge would be done before a student starts his/her flying (That was the way it was done in the military, where all this stuff came from). As an instructor I find myself dealing with students of wide-ranging ability, interest and prior knowledge. Some had no previous knowedge, did no separate study (tutored or therwise) and expected the instructor to take them through all the technical knowledge subjects, even objecting to buying the books for this.
Just as a flying instructor who does not brief/debrief is unreasonable, so is a student who assumes that the flight instructor will take him/her through all the ground school FOC.
Get the GS done first, it will save you as a student quite a lot of flying time to get your licence too.