My mother has a 64 year old Hachiya tree. When it was 10 years old my father dug it up and moved it to its present location. It's been mostly ignored in terms of pruning, other than cutting out dead limbs. It's got a huge clump of mistletoe at about the 15 foot level. Every couple of years it looks like its last but then it comes back the next year. 500 fruits would be an underestimate.
I have no idea why he got or kept the tree, he didn't like persimmons, nobody in the family does. Each year my mother gives away a few grocery bags full but the rest goes in the garbage. Maybe I'll try to make a few Hoshigaki this year.