That's in some sense a very good comprarison. In that sense that I for instance (having given birth to two children, one of them planned at home) absolutely don't think that everyone calling themselves OB or a nurse midwife does have knowledge or experiences to only do the necessary interventions.

If you go in with full trust to the personal then the chances that you get an intervention that you did not really need but some kind of procedure prescribe you anyway are very high. This is so in my country in Europe but according to my knowledge it is even more so in US, where constant baby monitoring via IV during birth is the norm and the rate of C-sections is one of the highest in developing countries.

Sure, maybe it all helps to ensure delivering an alive baby (although in US the death rates during or after birth are the highest in developing countries too), but whether the mother and baby get traumatised during the process - who cares.