Given the stated lifespan, and the cultural tendency to marry young, families ought to have a lot of generations alive at the same time.. but the older generations are thin on the ground.
They just had a magical war in which pretty much everyone lost a lot of their family, as noted in the earlier chapters.
And these are wizards whose power comes from knowledge, so this is often a world where Old Is Strong. We might expect older people (in good health, because of healers arts, as Harry notes when talking to Dumbledor eabout immortality) to be closer to the front lines.
They just had a magical war in which pretty much everyone lost a lot of their family, as noted in the earlier chapters.
And another one 40 years earlier.
And these are wizards whose power comes from knowledge, so this is often a world where Old Is Strong. We might expect older people (in good health, because of healers arts, as Harry notes when talking to Dumbledor eabout immortality) to be closer to the front lines.