Van Dijk is Liverpool's main defender. Saudi League will be popular because of another top player like van Dijk. More players will join the Saudi league, as teams offer big salaries for them. Some of these players prefer to stay in Europe.
Saudi league is already popular with the number of players that joined last season so what more will a player joining will add. Van Djik is a a very talented player and also experienced and joining the league will be a massive boost to the league and the team he joins but the question is, is Liverpool ready to let Van Djik go?
They have lost Kloop already so if they lose Salah and Van Djik this season Liverpool may go back to being a normal average team in the league and challenging for the title maybe difficult.
Saudi teams are known for offering a lot of money to players and that way it will be difficult to turn down their offers especially when the player has limited time to play for.
The more the merrier, I am sure if VVD joins, then the number of Dutch people who will watch this league will go up. Remember, this topic wasn't even created before Ronaldo joined, so nobody even talked about it before him, and now we are nearing 700 pages, all within span of 1.5 seasons.
The more players that they add like that, would be better. Of course VVD isn't as nearly popular as Ronaldo, not even remotely, but at the very least he is popular a bit and getting a player like him would make them a lot more popular. This isn't just a single player thing, it is more like mindset, if they keep adding VVD type of players constantly, and have many players at that level, then there will be more people watching the league gradually.