We can easily expect that women are created in a way that the way they reach shleimus is not through torah.
This addresses your question as well. If a woman learns torah, she will not become closer to Hashem through it. If she says she is, you know that it is not Hashem she is becoming closer to.Women can reach shleimus without lulav or shofar as well. But, don’t we have a concept of non-mechuyavim getting schar as well(gadol hametzuveh veoseh…so you see there is schar just a metzuveh is greater). I doubt you tell your mother these type of things about shofar lulav or davening. My understanding is that we consider it a good/nice thing to do.
As for learning, is it worse than sitting in a sukah(other than the feminist implications)?
You may answer tiflus, but that seems to be an issue with teaching and not with learning(though I imagine some may argue that point).
So, just like there is schar for shofar or sukah, why wouldn there be schar for torah study.
Also, as mentioned, why cant they have that exposure to hashem?