This thread is already quite tense, if we start tossing around blame and accusations it will get ugly quickly. Accusations that someone has lied when you have no solid evidence are a particularly good at getting things fired up, and it's a bad idea to through baseless accusations around in general.
I'd like to clarify that I think Brian Karis was entirely honest when he said he was devastated to have his talk canceled. I brought it up because it seems inconsistent with the story we're getting from these articles, but it makes me doubt the completeness of these articles, not the character of Karis. I doubt the story is entirely false, but it is unconfirmed and from an unnamed source - we don't how much of this information is first hand, we don't know how it could be biased, and we don't know if anything important is missing or was withheld. At best we have an incomplete picture, and as such I'd be careful treating this as hard fact.
Plus if they quit development wouldn't Bethesda have immediately moved on to another developer.
It's unlikely they'd have someone lined up like this. Even if they did the process of setting up a publisher/developer contract isn't something that gets hammered out in a matter of hours.