Modernizing Saudi society and making Saudi Arabia a global sporting hub are two different things and I hope you know that. The goal is to get people to think that both things are one and the same. Because they sign Ronaldo and other players that have been former European players makes people think that they are aiming at becoming more modern, but the truth is that most things remain the same while these players can enjoy a lot of privileges. Or do you think the average woman in Saudi Arabia would be allowed to live the same life as Ronaldo's wife? Lol of course not, I don't even want to know what they would do with most of them. The deal is that Ronaldo improves their image and in exchange for that they make him richer and richer.
Every country or region having own plus and negative; Saudi Arab were tight closed country for centuries due to have Muslims holy lands now current generation is looking for change about few things just and it's never been easy, so their approach is bringing this modernizing through sports is completely justified because they are going on right path and have fair chances of passing through this easily without any problem their recent huge investments are going to help them in long run.
Even this has never been easy but still they are going into right direction Saudi Pro League is having strong bonds in soccer with hosting FIFA World Cup things could be on another level and their investments in Tennis and Cricket is surely going to have huge impact on their culture and policies for future.