Multigeneration Familes in the WW

[prep0strus]

No: HPFGUIDX 173758

I've noticed that there rarely appears to be more than two generations
in any family alive at any point in JKR's books.  The Tonks family is
an exception - for a very short time, until that anomoly is corrected.
 I think we can also expect and hope for the generation we meet in the
epilogue to be able to meet their Gran and Gramps Weasely.  But in the
actual books, I have a hard time recalling grandparent interactions -
barring Neville, raised by his grandmother, after being effectively
orphaned.

Have there been theories as to why this is?  Does it simply expand the
world too much?  I understand that Harry needs to be alone, which is
why somehow all 4 of his grandparents need to be dead before he is
born (which seems very unusual, seeing as how Lily & James were not
exceptionally old when they had him), but it might've been fun to meet
Arthur Weasely's crazy father or some such thing.

Adults appear to be adults, with no one more venerable to turn to
within their familes.  I hope it's a tradition that breaks with the
newest generation.

~Prep0strus (Adam)