Everyone dies of something.
For the record, Parkinson’s isn’t fatal, or at least not like cancer, or a stroke can be. I’ve had the diagnosis for 5 years now. It’s a PITA at times, but not going to kill me anytime soon (like I’ll live another 40+ years if I’m otherwise healthy) and probably not even cause me to retire on disability for another 10-20 years (I’m 43 now). So far the only measurable impact on my ability to do things is that I have to limit myself to falling no more than 3 trees in a given day, as otherwise I risk having an anxiety attack. Otherwise I can, so far, work around the other issues.
Most PWP die with it, not from it. Those who might be said to die from it actually die from things like aspiration pneumonia due to swallowing problems, or from head injuries from a fall caused by their PD symptoms.
If Putin has PD I feel for him in that regard. Although it’s not a huge deal for me right now I know eventually it will become a much bigger deal. My uncle by marriage had PD, and at his funeral my cousin (his son) said he considered PD far worse (for the person at least) than Alzheimer’s because with PD you know everything that’s happening during the whole slide down. With Alzheimer’s at least, after a certain point, the person with the disease becomes oblivious to the situation. Now, for the family and caregivers Alzheimer’s is probably much worse.
My uncle officially died of a heart attack. One could argue that his body was simply worn out by 15-20 years of PD. But he had also been pretty obese (the man was a phenomenal cook - never trust a skinny chef) and he did lose a lot of weight in part so my aunt could help care for him. That weight loss and improved fitness might well have added more months/years than PD stole.