Yeah, it kind of got forgotten, I asked about it towards the end of beta and no-one even remembered they wanted to do something with single player.
I do remember that the game wasn't supposed to have any special SP offering at inception, rather it was a wish from Stardock's end that GPG do something with it. So I can't say I mind too much that the game didn't get any drastic changes part way, swapping lead dev's part way through and adding new ideas can lead to some badly mangled gameplay.