Reminds me of the old Picasso story;
Woman bumps into Picasso on the street and says “OMG its Picasso! Could you draw a portrait of me?”
He replies “But of course” and casually scribbles a few lines, shows her, and then stuffs the sketch into his man purse.
The woman brazenly asks, “Can I have it?”
To which Picasso replies, “Indeed, for $30,000.”
Shocked the woman responds “What? But it only took you a few seconds!”
And Picasso astutely points out “On the contrary Madam, that drawing took me my entire life to create!” and he walked away.
The story is a farce I’m sure, but the point is that those 20 year veterans who can pull off an unstructured interview are drawing on instincts and experiences honed over 20 years of conducting structured interviews.