I'm not friends with the developers. I follow this forum and listen when they speak.
Just recently faatal, one of the lead programmers, stated as much when asked.
From what I understand, adding factions before 1.0 would mean at least 2 more years of development, which I don't think The Fun Pimps are willing to consider.
Also, you can have factions, without having "real" NPCs, meaning that they could add job givers (like traders) also for the bandit faction, and call it a day.