By itself, this comment is not definitive. But, paired with the rest of the evidence, this comment is a bit more illuminating. Paul Oughton does not own Bethesda, but he is a publishing exec. He would know about future titles coming down the pike.
What bothers me about the Oughton comment (other than the problems it caused here on the forum!) is the timing involved. Let's assume that their next game is TES V - well presumably they would have known early in it's production whether they were going to upgrade the TES IV/FO3 engine or overhaul it. We know how that they went with the overhaul, or perhaps even a fresh start with a newer version of Gamebryo, and therefore would have known the game would take a while. Therefore the 2010 comment seems out of place.
I think after TES IV was released the developers started working on a design document for TES V and Oughton, knowing the developement process of Fallout 3, applied this to TES V and then unfortunately speculated openly about this. However a design document doesn't mean that production is imminent, Redguard 2: The Eye of Argonia has a design document as well and that game never went in to production.
I do have to admit bias here because the Oughton comment caused no end of headaches for us here. Still while this can easily be evidence that TES V was being considered I wouldn't give any weight to his time frame speculation.
True, and I sort of forgot about the rest of what I was going to say here. Todd has been talking about not announcing because "they don't want fans to get mad if something changes..." You could take this like the crossbow in AC, but I read into the fan part. A new IP doesn't have fans yet. Elder Scrolls does, and they would definitely let Beth know if they weren't happy with what the game looked like it was becoming.
I think he's referring to changes made during developement rather than between titles. Rather than the crossbow example from TES IV I'd use the shadow system: Bethesda initially showed off a very dynamic and detailed shadow system and then later replaced it with something much simpler. Despite the game being months off this causes a furor and even long after TES IV was released there were people who brought up Bethesda's "bait and switch tactics" and "false advertising" concerning the shadow system.
As for FO4, it would very much so surprise me to find them working on it. There is little reason for them to want to make the third FO game in 3 years (if it is released in Oct/Nov 2011). Not only would it T-off all of the TES fans, but it doesn't really make business sense for them to ignore a very successful, highly anticipated, and more-rested series in TES in favor of saturating the market with FO stuff.
Definitely, and given the time involved it seems unlikely that they could announce an Elder Scrolls game by someone else and really sate the fans.