Names are a funny thing.
When I was on the Twisted Nether blogcast, one of the standard questions Fim asked me was where I got my characters' names. Even though I knew it was coming --I'd listened to all but the last few questions* of a few episodes prior to my interview-- I still kind of muddled through an answer. What it boils down to is that I tried to create names that at least sounded Fantasy-esque. The each name's origin may be different, but the name itself arose from a desire to make something that sounded at least semi-realistic.
Every time I enter a BG and find the game populated with names like "Sukstobeu", "Ikeelthings" and "Hotsxyfun", I'm reminded that not everyone plays the game with the same goals in mind.
I've often wondered how much of a correlation there is between purely goofball names and a players' tendency to play certain aspects of an MMO. I suppose there are exceptions, but I don't often find players with XBox-esque names while I'm out and about in Azeroth, leveling by questing. I'm sure that once Pandaria drops that'll change, but right now it seems that a lot of these sort of names are concentrated in BGs, and to a lesser extent instances/raids.
While I realize there's a great tendency to pass these people off as merely kids or teenagers, I don't think there's a direct correlation between age and name choice. I can think of enough examples in the guilds I've been in that refute the idea that only kids play with names like that.
But what does stand out in my mind is that the level of immersion a player wants in a game does have an impact on their toon names.
Quite a few of the people I know who have crazy names don't really care much about lore/story, RP-ing**, or seeing a final raid boss down due to in-game reasons. They're not likely to be (non-battle) pet collectors, transmog players, or achievement hunters. Among the MMO bloggers I chat with, I don't think a single one has created a name like "MrCowCanMooCanU"***. But to me, that makes sense because we care about the games we write about, and we're not playing just to kill a few things and blow off some steam. Or show off our e-peens.
When we take time to create names that sound Fantasy-esque, we're saying that immersion matters.
There's a great temptation to make the leap from naming to immersion to longevity in a game, but I don't think you can connect the last two. There have been far too many people who have tried games and moved on to make an effective link there. Just because someone does care about immersion doesn't mean that other factors don't influence their game playing.
Still, I've never forgotten what one (now ex) guildie on Horde side once told me in Stonecore when I said "So THAT was what happened to Millhouse": "Q, I don't care about who they are, all I just want to do is kill them."
And you can guess what type of name his was.
*I figured I might as well be surprised by a few of the questions, and the famous "last three" seemed like a good idea.
**Erotic role playing (ERP) is most likely a different kettle of fish.
***Now having written this, I'd bet money that someone --probably Rades-- would name a Tauren that just to tweak me.