I think the sheer amount of groups usenet has is both a boon and a hindrance. on the one hand you can get a group for everything. on the other nobody is gonna read it, or even carry it.
the whole system suffers from this because it sprawled out in the '80s and '90s, and some of the topics just are not as relevant anymore.
who is actually using #os2 nowadays for example?
and yet the comp.os.os2 hierarchy has more groups than the comp.os.linux one.