Writer's block is simply a failure of ego

I am reading Let Me Tell You What I Mean by Joan Didion and she wrote that

“All writing is generated by a certain minimum of ego: you must assume a position of authority in saying that the way I'm writing it is the only way it happened. Writer's block, for example, is simply a failure of ego.”

I'd like to understand this more. I believe it is related to Writing is the act of saying I

Writing

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