I'm surprised no one has mentioned this yet, but new franchises logically SHOULD have better legs than established ones. People who wanted DMC4 knew they wanted it before the game released and got it on day 1 if they could. Same with NG2. Both games had existing fan bases that got on board right away, and the sales for both highly reflect that. That's even why both games were put at bargain prices so much earlier in their lives. HS, however, needed word of mouth to get around (just like Uncharted and LBP and all the Wii games and...) and some price-cuts to cover up how short the game was. With those, things were golden.
Really, though, the biggest detractor was simply how short the game was and that's not even a fair issue. Most games in its genre aren't significantly longer, and after beating DMC4/NG2 in a similar amount of time (both are about 10 hours) HS probably didn't look like too bad of an investment.
You do not have the right to never be offended.
