Twitter is really big there. It's basically the most used social media by a vast majority compared to other ones. It's way more plausible that some 'too much rich to know what to do with all the money' Saudi princes decided something like a few percent of their wealth to own the biggest social media on their country for bragging rights and admin privilege to be worth it. Plus, they probably thought Twitter was too big to fail and die, They didn't expect Elon would fuck it up so bad. I don't think anybody expected Elon to fuck it up so bad.