I would suspect that automatic updates and ensuring all your customers are patched to the latest version is a huge draw for companies as it would (normally) cut down drastically on tech support. The nearly idiot-proof self-install through Steam helps as well.
Given that the auto-updates seems to generate problems in its own right (see the post immediately preceding this one), and that patches also tend to break saves and mods, one could argue that these features represent as much of a burden on tech support as they do an asset. While a decision to effectively "not support their games themselves" might be facilitated, and seemingly attractive to a publisher, I like to get my support from the closest source to the designer as possible, and have found that these middle-man arrangements actually tend to create additional ambiguity and forms of evading customer problems.
Whether I am arguing against a Steam business practice, or against a publisher decision really is not the key point however, and my core question remains: WHY does Fallout New Vegas have to require Steam?
I do not want to participate in Steam, but I would like to purchase a license to play FONV. I continue to adhere to my refusal to participate in Steam, and therefore, have not purchased FONV. I've made Bethesda aware of this in a message attached to my most recent purcahse (Oblivion GOTY; Morrowind GOTY; and Rogue Warrior). I have great respect and admiration for Bethesda and the games they publish. I would happily buy FONV, despite _any_ reservations I might have about the game itself (and even in spite of the apparently awful game that is Rogue Warrior [still have not installed it]). But since I am expected to agree to become a Steam member in order to purcahse a license to play FONV, I will not buy the game.
That is one less customer for Bethesda, and I suspect I am not alone. Indeed, I can name at least a dozen forumites who share my sentiment on the 3 or 4 differnet game forums where I'm active. How many Steam users would actually prefer to have other options as well?
Even if there are 10 times or 10,000 times as many of you who eagerly participate in Steam, the fact remains that some customers are being lost by making Steam a mandatory part of owning certain game licenses. If the benefits of Steam to any who might benefit are not contingent on Steam being the exclusive source of distribution, then what reason is there for any game to be Steam exclusive? I can see no obvious reason other than that Valve benefits more, both in the short-term by sales, and in the long-term by outcompeting other distributors, by virtue of Steam exclusivity.