Demand capture
Demand capture is marketing aimed at people already looking to buy: search, ads, comparison and retargeting.
Capture is necessary and measurable, which is why it absorbs most budgets. It is also structurally competitive: you are bidding against everyone else who wants the same in-market buyer, and the cost only goes up.
A capture-only programme has a ceiling set by how many people are already shopping. Growth beyond it requires creating demand rather than harvesting it.