It's understandable for players to leave for Saudi league if they are offered a lot of money they won't be getting in other leagues. That's the only thing Saudis can do at this moment, the power of money in todays football means something and instead of buying a European club to build into something larger, they are making their own league bigger which is a smarter decision if you ask me but it's a costly one.
They are going to spend a billion dollars per year on these teams which is going to be a lot but when you consider Saudi family probably has close to half a trillion dollars, you realize that spend a billion dollars per year on this league doesn't really even crack their top ten investments and they see this more like a hobby. So they can spend a few more 100 million per year contracts and still would not even feel it.
The point is, they don't see this more like a hobby. I'm pretty sure, it's not without reason if they dare to pour out fantastic funds. after all, what they do is not just to spend money. however, there is a mission behind what the PIF and the Saudi kingdom are doing. the Saudi kingdom sees, if the entrance for their various projects through football. with football, all eyes of the world will be on Saudi. that's why, they are willing to spend a lot of money to bring in top European players. in addition to bringing the development of Saudi football much further, they also opened the door for other countries to invest in Saudi. which means, Saudi has been open to do business with countries around the world. that is why, 4 pro saudi league clubs were acquired by prince Mohammed bin Salman.
Don't we see that what the Saudis are doing is the right step. don't be surprised, if Saudi will become a destination country, just like Abu Dhabi. their current focus is to host the 2030 world cup, after which this country will be increasingly visited by many tourists. they don't just rely on religious tourism for certain religions, and don't always rely on oil. but they plan to expand into other industries that will bring in a lot of money. But, this is just my personal opinion. So, our focus is on football, at least in the next 5-10 years, Saudi football will be much more advanced than other Asian countries.