Sourcing is key because every step introduces error. And you misunderstand: Atwood to Konkvistador would be a fourth-hand, if one wanted to include it. Count the steps.

In fact, I did look at the book and I assert (sadly) that nothing was lost in Kevin Kelly's transcription.

So then, it's essentially worthless. There is no citation, no context, nothing to situate it in any time, place, country or year besides 'the 20th century': we can't even tell how many steps we are removed from the origin since you say there was no context like "many years ago, an old friend of mine was taking a pottery class".

Just another persuasive parable floating around.

I'll stick with Ericsson's research, thanks. Mindless practice is not useful; deliberate practice is useful.