I suspect they had been planning on eliminating or redistributing Steemit's stake, which is why Ned wanted to sell, but they probably wanted to keep control of the chain rather than building a new one.

Yeah, I agree. I remember they had even talked about something like "forking Steemit out" a year or two beforehand. I guess they never really gave up on that idea.

and then they could claim that theirs was the "real" Steem chain and Justin was the one splitting off a new chain.

Some of them even tried to make that claim anyway.