Yes, there may be technical limitations that required processing to happen on EA servers. And yes, they make it clear on the front of the box that an internet connection is required to play the game.[1]
But most people purchasing this game expected that for the most part, this would be primarily a single player just like the previous titles, and that the internet connection is only required for DRM and/or occasional online interaction. They don't realize that a lot of the engine lives in the cloud.
So there is a different level of disappointment because of the expectations that were there. If this had been a follow-up to an MMO, they would have known that the game heavily depended on server performance, and it may have been a little more forgivable.
But most people don't understand why the game doesn't work. "Just disable DRM for now. Or disable multiplayer interactions. Make it offline only for now."
What I can't believe is that this isn't just minor hiccups with the launch -- this is catastrophic failure. Why couldn't better load testing simulate and predict what they're seeing today?
Regardless, as many have said, this will ruin the name of Sim City, at least for a period, and will cause even more bitterness with EA than what already exists.
[1]http://ecx.images-amazon.com/images/I/815mDnNUDhL._SL1121_.j...
