Isn’t the whole point that they’re tightly intertwined? You pay to advertise in the relevant search results of your customers.

That’s not the law, so it’s irrelevant to the legal issues.

I don’t mean the law. I mean how the actual ad/search product actually works. As a Google customer I pay them to present my stuff the way I want it to my customers when they search for stuff about the things I sell. That’s the product, no?

That’s not relevant to the monopolization claim here though.

On the contrary, antitrust law has a lot of rules about using dominance in one industry to prop up another.