As I have said there are many reasons and risk hasn't been mentioned. However...
I have an acquaintance plays guitar for a living. He has been pulling 60 hours a week at a Hermes depot during the pandemic.
Was reprimanded on day 1 for taking too much care of a parcel. Literally told to throw it, there was enough time to walk and place it carefully.
He has horror stories a plenty and has vowed he will never, under any circumstances, ever post an instrument again.
In his opinion every bass you receive undamaged is like winning at Russian roulette.
Now, I have only ever received one package with the contents utterly destroyed so your stats may be quite right.