I never used BitKeeper or TeamWare and consequently don't know how their capabilities were similar to or different from arch's at the time. Did you use them?

Tom had a pretty clear vision for arch which is more or less what Git ended up achieving. Everything he wrote publicly about it derived the feature requirements from his social agenda; he never mentioned BitKeeper, and I don't think he knew about it. He must have known about TeamWare, but I don't know if he had ever used it, and from the little I can glean, TeamWare lacked some very significant things crucial to what we think of as a DVCS today. But maybe I'm wrong about that.