Jewish Law represents the accumulation of our national wisdom and the repository for our experience as a people. We are unique in our identity as a people with a particular relationship with God and with history. Whether any particular halakhic decision is made by a rav in response to circumstance or goes all the way back to Moshe and Sinai is irrelevant; all are part of our cultural DNA and are no less God-given than our physical DNA. It is quite literally a part of us. And we are a part of it. We all have an input to the halakhic process just by doing or not doing.