From free listings to paid
Product listings began as free organic results, became paid, and have partially returned as free listings alongside ads. That is why Merchant Center exists separately from Google Ads at all.
From manual to automated
Standard Shopping gave granular control by product group. Smart Shopping abstracted it away. Performance Max absorbed it entirely, adding surfaces and removing visibility.
Why this matters now
The controls you are looking for often exist — in the feed rather than the campaign. Custom labels, priorities and exclusions are the remnants of the granular era and they still work.
Which is why feed work keeps outperforming campaign work.