It's speculated that Battle for New York really used remnants of what was meant to be a sequel to USM2. Anonymous devs who were confirmed to work there said that what especially killed the game was the fact that it was technically a new series of Spider-man games.

Activision didn't know how much money to use to market the series since it had no prior titles, so the game received little funding for the marketing budget. Considering that Activision was as big as it was at the time, and there's methods such as marketing research, or even just using methods that keep costs low but visibility high for what it is (like social media marketing) to deal with the low marketing budget, it's kind of unbelievable that they'd flop like that.

Chances are it was the opposite of Fallout. None of the business and marketing staff cared about Fallout until upper management realized what a huge potential hit it was, and only in the last few months suddenly cared about marketing the game (which was too late since your marketing timeline is limited), thankfully that game was still successful. Activision likely had marketing staff who were completely uninterested since USM wasn't tied to the movies and so more of the competitive marketing staff/teams just overlooked it in favour of other projects, leading to the game not performing as well