Pep doesn't say who he wants. He says WHAT he wants.
For example, Ruben Dias, signing of the summer, right? Pep wasn't spending his very scarce time scouting CB's all over the continent. In working with his technical staff it was clear a CB was needed, Txiki Begiristain and his staff identified Dias as someone with the qualities necessary to thrive in the kind of football the whole operation has been built around playing, and Begiristain went out and made the deal.
Pep is a figure of such stature at City that if he wanted to kill the deal, I dunno, he probably could have (maybe not, who knows). But why would he? He is in full alignment with City's technical staff who he worked with at Barcelona and who brought him to the club, and there is total trust in both directions.
Maybe it is Pep that wants Kane, but if the cost in money and/or players doesn't fit with City's project, it's not going to happen. It would only get to that point if there was alignment between all the relevant parties anyway, and a deal of that magnitude obviously bears a higher degree of scrutiny.
A manager going to the board and saying "get me player X and player Y" is dinosaur age stuff.