I've spent some time on genealogy, and really beyond grandparents and maybe great grandparents it's mostly curiosity and for the interesting stories, and I only care about the graves to the extent that it makes solving the puzzles easier. It's not like there is anyone alive in my family who knew older ancestors of mine than my great grandparents.
For my part I've only ever seen even my dads grave once, and feel no need to go back there, though I understand why some might feel it matters to have the grave of someone they knew in person because of the emotional attachment.
It's a bit of a paradox: burial rites are among the earliest and most fundamental elements of any society we know of; but long-term maintenance of burial sites has always been a challenge. That's probably because, after all the fanfare to honour the dead (which is mostly a way to minimize immediate social disruption), everyone eventually moves on.