Why are women exempt from (many) time-bound mitzvot?

Women are generally exempt from time-bound mitzvot (Kiddushin 29a). I have heard two reasons for women being exempt from time-bound mitzvot and both seem problematic, so either there are additional explanations or I am not properly understanding these two:

1. 
   

   Women have to spend time on maintaining the household and raising the children, so they do not have time for time-bound mitzvot. But if that's the reason, the rabbis could have said "those with child-care duties (etc) are exempt". As it stands, women with no children don't have the reason but are still excused, and men who have child-care duties are still obligated. (Granted that the rabbis of the talmud were probably not considering this latter case.) It seems odd to me that a stay-at-home dad is obligated while his teenage daughter is exempt.

   
   



2. 
   

   Women are on a higher spiritual plane and do not need as many mitzvot. It seems surprising to me that we could make that kind of statement about all women (and the converse about all men). Just looking around at the people I've met, there are wise men who seem not to need extra help and women who struggle and might need the help of more mitzvot.

   
   

If one of those is the reason, what am I failing to understand? If neither of those is the reason, what is? Why are women, categorically, exempt from these mitzvot?

Answer

The technical reason is a Gemara in Kiddushin that says that since women are not obligated in Tfilin (which is mentioned in a verse near the verse that speaks about Torah learning, where it says (Vshinantem levanecha, you shall teach your son(and not your daughter))), which they are free from because , they are not obligated in any commandment similar to Tfillin. Since Tfillin is a positive commandment which is time-bound (one can't wear them on Shabbos/Yom Tov), so too women aren't obligated in all positive commandments which time-bound.

However, even after this technical answer (women are free from positive time-bound mitzvos) women could still ask: "Why should I lose out the benefits of Mitzvos? Mitzvos connect me to Hashem?" This is where the answers that you mentioned come in. Since women are not obligated in these mitzvos, it means that the connection one could accomplish with these mitzvos is accomplished on its own. (For a similar idea, when we aren't allowed to blow Shofar on Shabbos, Shabbos accomplishes what the shofar does, but on a higher level.)