I think you've misunderstood my post.
I didn't say 'luck' isn't involved at all.
I said that alongside luck, there are elements a woman does have control over.
For example, at the NCT class I mentioned, the 6 of us who were low risk, with straightforward pregnancies, had the option of delivering at a MLU along the road, or in a large regional hospital 20 miles away. The MLU was staffed by a small team of midwives, so anyone having their antenatal care there knew everyone in the team. I knew before going into labour, that whatever time I ended up going there, I would be met and supported by a familiar face.
On the other hand, the regional hospital had dozens of midwives, and the chances were, when you turned up in labour, you wouldn't have met the midwife before. Also, the midwives at the MLU were all highly experienced, they weren't in training, or newly qualified.
Given that a familiar, experienced, supportive midwife is one of the factors which contributes towards a postive, natural birth experience, it's clear that choice of where you deliver is important. All 6 of us did have the choice to deliver at the MLU - only 2 of us took it. It seems a bit of a coincidence that we were the only 2 who ended up without major interventions like epidural and ventouse.
Sometimes there aren't choices - but often there are. The majority of births are medically straightforward, ie, there are no complications and the woman has the potential to give birth naturally.