The issue of proof is very different from the issue of learning. I thought it was the latter being discussed.
There clearly exist methods for solving problems that have nothing to do with mathematics. This should falsify your thesis.
A: Knives are for eating.
B: Eating is only a part of it. Knives are for handling food.
A: You can handle food with a fork. Your claim is false.
Specifically, "math is for solving problems" does not imply "problems are only solved by math".