I would have to respectfully disagree with this assertion. The Thief series (which I love as well), is nearly as old as the elder scrolls, and is quite popular, not to mention it has a large modding community to this day. Plus, a lot of us have been wanting a proper sequel for a long time, especially after they crapped all over the franchise with TDS. Not to say that I don't agree with you 100% about it not being Thief (it won't be), I was just citing it as an example (although, except for the "announcement" part, it does meet all the other criteria you listed). My main point is that Bethesda has been kinda toying with us for years, and I don't think I'm quite ready to get my hopes again (although I have to admit that recent interviews are swaying me a bit).
I've just learned not to read too much into what Bethesda does publicly. Case and point: remember when they announced the books based on the TES series, and people were rabidly posting on the forums "convinced" that TESV would be announced within weeks, if not months? I just don't think it will actually happen until sometime towards the middle of next year. However, I will happily eat crow if it does.
Hmm, yeah you are quite right.
Oh! We shouldn't forget the 4 pages on Jan's issue about Elder Scrolls. Why bother writing an article if not to rise the hype and prepare for an announcement?
And I know that have been moments that we thought TESV would be announced, but if you look back the "evidences" supporting it were slim, now take a look in what we have now, a lot of things points to an announcement. I remember when we were debating whether TESV or Dragon Age 2 was going be announced. We got Dragon Age 2, but we were pretty sure that Dragon Age 2 had a bigger chance of being announced, the only thing supporting TESV was the tweet that said the next cover would be fantasy-ish. Now, we have not just ONE but 4+ tweets that can support it plus interviews and stuff.