A large set of small loosely-connected groups is an alternative. Groups can communicate with other groups on a need basis. This might be a pipe dream. Some would argue that the emergence of an uber-group that every other group must subordinate to is imminent.

no it's not, broadcasting is linear, alas its not strictly parallel.

Each person can broadcast at any time. So at any time, it's possible to have N^2 messages being sent around the company.

That's a non-sequitur, I guess you mean if every sender sends one message per listener. I don't think it's a broad cast if it targets sole recipients per message.

Quite literally, I think, it could be modeled as a vector space in linear algebra. Each signal is in frequency space, which can be found from the fourier transform integrating the temporal space over different bandwidth channels per sender. You get N² only if the message size is proportional to N, if you will.

a Fourier transform of channel