I don't understand why Prigozhin didn't create himself some protection.
Sure, he can't go after Putin himself, but what if he set up funds for assassins to kill Putin if Prigozhin ever dies under suspicious circumstances? If he says "I leave my fortune to whatever SUMBiCH (or their next-of-kin) that takes out Putin, and provides a guaranteed way of payment, I would expect Putin would think twice.
Sure, he can't go after Putin himself, but what if he set up funds for assassins to kill Putin if Prigozhin ever dies under suspicious circumstances? If he says "I leave my fortune to whatever SUMBiCH (or their next-of-kin) that takes out Putin, and provides a guaranteed way of payment, I would expect Putin would think twice.