Most people thought India were favourites, apart from ultra-pessimistic England fans (and even they probably knew deep down that England should've won but were too scared to say it), though. That's the thing. The overwhelming likelihood was that a team in England's position would win. Far, far more than 6 or 7 out of 10. I'd say 19 out of 20 at least.
Even in the last 6-7 years, fourth-innings totals as high as those are precious few, and that's not because of the pitches, it's because of the sheer crushing nature of the task at hand. In fact, you know, totals of 400 are still in the minority even now!
India were rank outsiders. Anyone who picked them to win picked lucky, simple as. And as I say, it's somewhat of an insult to a sensational performance to essentially say it's something they should be expected to pull-off. What India did last Test was something you are never, ever going to see very often, whatever direction Test cricket heads in.