The web's physics set the physics for all consumer software today, the assumption of the same origin policy.

The same origin model: it's safe to go to a new place, because the new place starts with nothing.

A startup has to start with zero data, a cold start. But the aggregator already has the data, they can start off with a massive unfair advantage.

This advantage dominates the "actually a better feature" advantage, and becomes "already has the data".

The bar to clear of "already has the data" gets steeper and steeper as the aggregator has more data and the average new app has none.