I don't know for sure but I think Ronaldo is still without a major success in the Saudi Professional League, isn't he? I am not talking about his individual trophies as best goal scorer, but did he win any important titles there so far? I remember when I thought that Al Nassr must be the Saudi super power club when they bought all these players, but it looks as if the league is more equal among the teams than I thought at first. He probably isn't too happy about Al Nassr's overall performance, but his salary probably dries the tears. 
Is he that broke that he should be chasing after money at this stage of his career. He's supposed to be creating a legacy and I think he realized that now therefore, him leaving the club should be under considering if he doesn't win any major silverware this season. His mates are winning things and increasing their achievements and if he's still after the money, then he's slowing turning into a loser which isn't something Ronaldo is known for. He needs to be at his best for the next world cup because he now has a team that have a chance of winning it therefore, hok playing at his very best is very important right now than before.
Ronaldo has built a legacy for himself long ago. You could argue both ways, but the truth is that he is still collecting goals as he wants to be the first striker going above 1,000 career goals. I think he will be able to do that unless he gets injured or something, but that is not very likely.
If someone has $500 million in the bank account and then gets offered $200 million per year, it still makes sense to accept that offer. He could make as much money again in two years that he made in 20 years before that. And not to forget that he isn't risking anything, he is going out there and doing what he loves the most while making the most money possible. That is not about chasing money in the sense that he needs to do it. He is doing it because he CAN do it. I don't think he would be doing it for $50 million per year, but $200 million per year plus all the extras and benefits coming with that contract? He couldn't say no to that.