Sounds like you're the one with the problem, not the kids. Your apartment isn't properly soundproofed for you to use as an office.
You haven't described a problem for the families with children, you've described a problem for others (you) who are using the building in a way it wasn't designed for.
Yet kids are required to keep the species going, so society needs to support their existence. Again, this isn't a problem for the kids; it's a problem for their neighbors who had an unrealistic expectation of living in a perfectly quiet place in an apartment building.
Kids yell for extended periods of time. Not all kids, but a large number of them do. If this is a problem it isn't with the kids. Demand better buildings.
Precisely. Architecture and construction can be improved, but kids are always going to yell. And unless you really believe kids have to live in detached housing, the answer is obvious - fix our environment to keep kids from annoying their neighbors.
You haven't described a problem for the families with children, you've described a problem for others (you) who are using the building in a way it wasn't designed for.