Avoiding the obvious semantic exercise, I think the child development experts have warned that the longer this goes, the more (potentially) damaging it is to children - and for different reasons at different ages.
They're isolated from their school life. They're isolated from their friends. They're isolated from the social events. These things are important not only for kids' well-being but for their psychological and social development. The longer these really significant distancing measures (e.g. schools closed, group activities like camps and parties remain unavailable), the more likely it is that some kids will suffer meaningful impact.
I have a 5-year old and a 7-year old. I'm not too worried about it now, but I do have real concerns about if we end up in another state of emergency in the fall.