The idea that billionaires are not actually billionaires because they cannot possibly sell their shares is not real.
In principle, Bezos could be in this because he values journalism and wants to promote it. There is no reason why this couldn't be a patronage system where one of the richest people in the world spends their money on something good for society.
Sure I suppose anything could be someone’s passion and that could explain why any amount of money would be spent.
But according to the article he is actually concerned about the amount, and I’m agreeing it’s a justified concern.