They've signed Cristiano because ppl who're following him on social medias will follow SPL. They needed Cristiano to give SPL exposure because they wanted to host the world cup. Al Nassr's got popular because they've got Cristiano. They've kept him in SPL because advertisers & sponsors want to have association with SPL.
Cristiano's signed a mega contract with Al Nassr he's staying for 2 years. I don't know they've given him shares in the company he would've stayed because other teams can't give him mega contracts. If Al Nassr don't win their SPL it won't be considered successful signing.
There could be other goals when bringing Cristiano Ronaldo to Al-nassr. That is, it is not only in the interest of the Al-Nassr club to strengthen their team. But another goal is to make the SPL a more famous league thanks to the popularity of Cristiano Ronaldo. And the mission has been very successful so far. And apart from that, Al-Nassr was also helped by the presence of Cristiano Ronaldo. It's just that this team has always had problems at the back in the last few seasons, which has made Al-Nassr's excellent goal productivity quite in vain because the number of goals scored against Al-Nassr is also quite large. But it seems like this team still feels they are benefiting even though they always get less than optimal results. Because financially and in terms of popularity, we certainly understand what impact Al-NASSR and SPL have had because of Cristiano Ronaldo. More sponsors and the like bring greater profits to clubs and leagues. So it is not surprising that Al-nassr dared to extend his contract again with a bigger salary.