...plays similar and feels mostly the same as the original boxed release version on 360/PS3.
I bought both.
Also the whole point is the online thing, now I don't have gold membership for my live account at the moment, but when I did I could never get a game...
...again suggests a lack of people playing it.
Lack of purchases really isn't a good reason for putting it offline. It's also still up on PSN and is even priced off at the moment.
If you've bought it you can still download the game by going through your download history, same with everything else removed from XBLA, PSN and Steam.