I feel this. That said, I’m terrible at including kids. I have been feeling NPC-fatigue lately, just exhaustion trying to remember which NPC acts how. So adding more than parsimony dictates feels scary.
Anyway, in one of my cough cough favorite settings, there’s a distinct lack of kids in the source material: Regency fiction takes an almost complete “neither seen nor heard” approach to kids. But obviously, they existed! As did, say, servants, who also get hidden out of the period stories for the most part. And in both cases, I find modern stories are enriched by remembering that they’re there.