personally i think most people tear because of purple pushing or otherwise not just going with what their body wants to do.
My I have had an epidural twice although the second time I wasn't flat on my back. Neither of them was in the position or the rhythm for pushing that I would have been on my own. My second birth I had no pain meds, but still was on a bed (again not laying down though) where I didn't want to be, I wanted to be upright... so not listening to my body directly.
And yet no tears. I should've from a statistical perspective, torn at least with my first. My third was over 9lbs with a large head and again an epidural for birth and no tears even though I "should" have if you just look at the birth variables.
But pushing over an intact perineum my body does really really well I can't really take credit for that, it just is.
Going into labour on the other hand... well... I'm 3 for 3 with having (twice medically necessary, once for prolonged SROM) an induction.