I specifically excluded SPY in the last paragraph as a "productive" investment, but only for the sake of argument -- I admit I'm inclined to agree with you that

I specifically excluded SPY in the last paragraph as a "productive" investment, but only for the sake of argument -- I admit I'm inclined to agree with you that even passive investment of this type is productive. I think the problem pointed out by the original article is that they don't like this because it tends to produce oligopolies (i.e., "chains"). Unfortunately, I think that's just because non-colluding oligopolies are efficient. So the market is "working," some just don't like the outcome.