Not sure, but 4 co-authors is a likely partial reason. Also I guess partly due to imitating various precedents, and not just in tech. E.g. The Three (Musketeers

Not sure, but 4 co-authors is a likely partial reason. Also I guess partly due to imitating various precedents, and not just in tech. E.g. The Three (Musketeers, ...), The (..., ...) Duo, The Famous Five (kids novel series), etc. A separate HN thread on that might be a fun read :) A similar one is eponymous Laws (Wikipedia has a list).