If a small child is stopped or not able to go and see their beloved GP as they are too small to go alone, by the time they are old enough, the GP would by that time be strangers, so therefore the child wouldn't choose to visit.
The golden time between GP &GC is from birth to about 12yrs, after which youngsters go their own way, off with their friends on adventures, GP now seem boring, all quite normal. They still love their GP, but now friends come first.
As the GC grows into adulthood, they may delve into genealogy and then become interested in their family history & therefore their GP, by which time the GP are probably gone. Also if a child has grown up knowing there is animosity between their parents and GP it would naturally put them off visiting the GP. Until they learn otherwise.