The endstate of aggregator business models is retail media.
"Retail media" is ads within the aggregator's 1P UX.
This business model has insane margins because the inventory is the aggregator's own inventory.
Small-scale aggregators like Instacart work this way–though a user might not really realize that they're seeing ads.
But also the largest scale aggregators mainly work this way, it's just that the ecosystem is so large and rich that it's more obvious they're ads.
Things like MCP and agents erode the aggregator business model; if the users eyeballs never land on the service, they can't be steered.
That implies that aggregators will resist being embedded in tools like MCP.