Because the platforms took targeting away and got better at it than any media buyer. Interest stacks and lookalikes are mostly nostalgia; broad delivery wins, and what steers broad delivery is the creative itself.
Every genuinely different ad is a different targeting instruction: the dog-owner hook finds dog owners, the price-skeptic hook finds price skeptics. That is why accounts with 10 new ads per week keep finding new customers while accounts with five ads a month exhaust their pocket and stall.
