I don't think your being unreasonable at all. I had exactly the same problem with my parents (it has got better but not as good as I would want).
My main grievance is/was they had my grandparents chomping at the bit to look after us, they had us for countless weekends, took us on numerous 2 week holidays and had us to stay lots in the school holidays.
My parents must have had a ball all the free time they had. And they lived 30 minutes away (in the 70's that was quite far) and both my grandparents worked. So not your not being unreasonable. Sometimes life just aint fair. Wait until they need nursing in their old age - tell em you don't want to ha ha!