To answer this question you have to broaden the scope to comic hero games in general. Your spiderman games, your hulk games. Most of them were B-level games, not AAA games. The general attitude of companies like Activision is that quality didn't really matter, and there's evidence to back that up. Spiderman 3 was an atrocious game, Spiderman: Web of Shadows and Ultimate Spiderman were pretty good games. Spiderman 3 completely murdered Ultimate and Web of Shadows in sales, because it rode the hype of the Spiderman movie. With numbers like these, why ever take the effort to make an Ultimate/Web of Shadows level game, when you can just produce garbage like Spiderman 3 and make tons of money?
But to use gamerankings terminology, the quality bar Activision was playing with was between a 65-ranked game and a 75-80-ranked game. (Or in the case of, say, Hulk: Ultimate Destruction, an 85-ranked game). Eidos asked themselves "what if we cranked the quality way higher; maybe Activision is wrong and quality actually DOES matter to sales, but only if we give enough money to make a 90-95 ranked game". So...they spent a crapton of money on developing Arkham Asylum (which ended up with a 92) and it...sold very well. So they got even more money to make Arkham City (which got a 95).
And that is basically what happened; it was a business gamble that paid off big. The moral of this business story is that for comic book games, they'll sell about the same if they're anywhere in the range from "bad" to "pretty good". You have to get them into the "ridiculously awesome" range before quality actually starts to matter from a sales standpoint.
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Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision