This does happen, but it makes things extremely confusing for new users who weren't privy to the drama that led to the fracture.

Consider these: r/news

r/worldnews

r/neutralnews

r/fullnews

r/qualitynews

r/worldevents

r/inthenews

r/anythingoesnews

Eventually the subs become more and more specific and devolve into echo chambers. For whatever reasons, this seems common among philosophy/opinion subs and doesn't seem nearly as prevalent among topical subs.