That isn't really anything to do with Juventus though, is it? That applies to every team in every league if a selling club wants to not sell to a rival.
As long as Kroenke and Usmanov are digging in at Arsenal they won't be going on a huge spree. They can spend €20m-€30m on a player if they want, there is no question. But it would have to be for a wonderkid or slightly older, as Wenger always has to develop players.