"You're truly better off $$$-wise to just run the AP stories or copy-pasting your competitors stuff." This is gist of the problem.

As an aggregator you have a lot of upside and little downside, as you mention 'simply linking to coverage you can't match in house may save you money, but you won't make any off of it' but some are making considerable money with little downside.

The act of 'creating' the content takes a lot more resources, creating a greater downside. With aggregators much of the upside is taken away, there is no more exclusivity.

There is a reason why tabloids and TV networks pay 'exclusive rights' for pictures and stories, to woo advertisers with unique value. If the story is being run everywhere the value is split. The greater risk is taken on by the content producers with aggregators vying for a piece of the traffic that advertisers want.