If this is true, why, for the majority of human history, was writing a high-echelon elite skill? If "pre-wired", why did not most just pick it up on the fly?

Unless you have Dyslexia

I think this is an interesting area of research...I wouldn’t think any actual conclusions can be drawn from these findings, but it’s certainly a possibility that over eons, our ability to be receptive to both speech and recognition of written language has been heightened as part of our evolutionary process. .

IIUC, it is not know when humans acquired language (and even much later, written language), so I don't see the evolutionary aspect of this.

It would be interesting to hear their explanation of people with dyslexia.A friend of mine claims that when he was in the Navy in Japan that one of his buddies was dyslexic and that enabled him to learn to read Japanese very easily because it was pictorial.

Hmmm..... Pretty tenuous, I feel.