Could have been timing too... I was just entering high school in 1976 but my older brother Patrick was graduating and he was my main music influence. I used to play his records for years before I started buying my own. He was into Zep, Deep Purple, Aerosmith, etc. but never Sabbath.
You know, thinking about it, it might have had something to do with their faux "devil worship" shtick, which would have been frowned upon by our parents. I remember bringing home a 45 rpm single of Zep's "Whole Lotta Love" and cranking it up on my family's console only to have my mom storm in, rip it off the turntable and force me to return it. It wasn't until many years later that I learned why she was so upset at 8-year old me screaming, "Gonna give you every inch of my love".