Well, both my grandfathers died in the 1960s, before my parents had gotten married and started having kids. And my paternal grandmother died, when I wasn't even ten months old. So even though I once saw her with my own eyes and she once held me in her arms, I don't remember her. But my brother was fifteen years old and my sister was twelve years old, so of course, they remember her.

. But to sum it up: Out of my four grandparents, I only ever got to know my maternal grandmother (who was the youngest out of the four and also was the only one of them to turn 90), who lived until I was eighteen and a half years old. So you don't always have your grandparents around as a kid. However, James and Lily were only like twenty years old, when they had Harry. So their parents couldn't have been more than 60ish at the time. And then, James's parents were a wizard and a witch, and who knows how long they can have children? So all four of them
shouldn't have been dead. But of course, this opened for the part of the saga about Harry's miserable upbringing with the Dursleys. But thinking about it, JKR could have given him one grandparent, who still was alive during his childhood, so he could have felt love from somebody...
But this also reminds me of something, that my sister and I have wondered: Why doesn't Harry care about his grandparents? He sees them in the mirror of Erised in book 1, but after that, he doesn't seem care about them. Like when Sirius talked about having lived at his father's place, Harry should have asked a million questions about his father's parents. But he didn't. And in Snape's memory in book 7, he sees his mother's parents, but he doesn't seem to care. This is very strange to me and my sister, as we're genealogists (or at least, my sister is).
*My 100th post!*