If dishonoured is any good, it'll sell fine.
Unfortunately even in our time word of mouth does not save video games. So no, you're wrong.
The only way it could fail is if it is not as good as it is made to look.
Or bethesda screw it up. Which they could, given they fail the best games they publish. That is a very real possibility.
They have no QA, do no testing whatsoever, so it'll be a bug riddled, unplayable, mess, possibley. Arkane are going to have to do their own testing. Because bethesda think broken, crashing, lagging, bug riddled, flawed games are acceptable condition and fit for release. No other or few other company/ies think like this, they test and fix their games. Bethesda think beta level is acceptable.
They're good at overhyping things, bad at testing. They don't even try to test games.
I see you know absolutely nothing about the QA and the testing behind Dishonored and your bias and prejudice shows it. Also Bethesda had barely any involvement in the project and let Arkane have some breathing room. Very good choice.
And of course there's the too much hype, not enough content thing. They probabely paid those reviewers off.
And the possibility the games not even close to being as good as it is made out to be.
Then it deserves the low sales it gets.
That is likely.
I love when people cling to these ridiculous conspiracies. Do you know how risky that actually is and that almost nobody has done it? We've seen more than enough gameplay, more than most games care to show and we've had constant Q&A from the developers themselves which info turned out to be 100% accurate. And you actually think scores show an objective and complex opinion? They really don't.
Dishonoured is wayyyyy overhyped. People are reading too much into something no none paid up people have played or seen.
I don't even know where you got this idea from. The game knows exactly what it is and it is showing it in the best possible way there is. We have a lot of gameplay footage, a lot of information and a lot of insight from both the developers and people who've tried the game out. People should be fairly aware of what the game is by this point and if you want to look at overhyped games just take a look at the mainstream market.
Recently a new trailer was released about Borderlands 2 that showed many of the features of the game. What it actually showed was the old game with a new skin. While there is a bigger variety in environments, enemies and guns the basic formula is still the same. The problem is that they market that as new. It feels like even a game like Borderlands can suffer from its success and put out a bad sequel that is basically what can be described as an Expansion Pack at best. I will still buy the game and most probably like it but at least I know I am going in for the same experience as the first one and not something revolutionary and groundbreaking.
Moderation in everything and try to adjust your expectations.