HI:"If so many of us are 'selling', presumably without any training whatsoever"

This is true in regards to what you are selling.

Remember Married with Children (TV show). Al was a shoe sales person and after does it fit I imagine you say how good it looks on the person and how much better the shoe costing 2x more would look.

Lets say you are now selling an electron microscope. Since I was on the receiving end of the pitch,
I can speak with some authority. The sales person was amazing intelligent and helpful in other aspects of what the task at hand was.

They got the po.