my guess is that gulf state monarchy investors (Saudi, Qatar, UAE etc) haven't been satisfied with the profit margins and are demanding more control over the companies, whereas American/European investors are possibly more focused on market share

could be rising competition from Chinese tech companies as well

It could also be a collapsing bubble where everyone's realizing personal data sold to advertising companies isn't as valuable as everyone assumed it was 15 years ago. They ran out of people to scoop data from. Everyone's already got every possible type of targeted ad pointed directly at their eyeballs 24/7. The market is cornered and there's nothing left to speculate on