The ecosystem itself should be the aggregator.

The problem with aggregators is not the gravity well, it's the "single entity in control."

That's required due to our default privacy model, the easiest way to safely share data is to have a single entity in control

Because when data crosses a legal entity's boundaries that's dangerous and high friction.

But if you could have data safely transit across origins then the ecosystem itself could be the aggregator, without the downsides of any one entity being totally in control.