Like I said your still talking about the majority using it, with 60% of the people that own a 360 also use online. And thouse numbers came out in January, Thats pretty impressive, it's probably more by now. It shows even beyond the #1 multi player online setup they have a good chunk of people with access to the other features of online such as the download content and chat.
What kind of sales have they had with arcade/marketplace so far? I havent came across a sales figure yet. Without these online customers and sales of online games and products Xbox would be a mear shadow of what it is today. Ignoring that makes you a real fanoy.
I guarantee you Nintendo is no where Near these numbers for users with online, even when its offered Free and with more consoles on the market. I know both my brothers in law don't have it, even after they saw what you can do with it on my systems. Heck I even gave one of them the Nintendo dongle to hook it up and he ended up never using it.
Maybe as more features come out like Wii-ware and stuff but honestly I don't think the "casual" gamer will get hooked on the Online/DLC untill it is a key player and not just an extra for a console, which isn't going to be this generation.
You have to understand all 3 systems have their die hard fans, the people that want every option offered, and everything given to them improved apon. But this is not the majority this is the smaller amount of fans that buy up everything. The key with xbox is these same minority of fans acctually direct the way the console does move forward, and the casual gamers on the 360 acctually follow suit with the die hard fans if they want to or not because that is what MS offers. Probably why alot of people end up listing the 360 as the "hardcore" console.
Nintendo on the other hand follows the majority and the majority of online users mainly hop online for a VC game so far. Even then it's not huge numbers when related to console sales.
If the sales of online games where better or when the DLC increases in sales that is when Nintendo will invest more in online. If you want more online honestly you have to start buying up more online products, good or bad, you have to show Nintendo its worth it for them to continue to invest in online, otherwise they will not take the risk if its not needed.