Not true. The actual Reddit[1,2] posts the article pulls this from says they have been able to sync their game to the servers. It seems that when offline, it saves it locally and uploads upon reconnect. He was able to remove the 20 minute timeout disconnect, but it still saves things locally and uploads upon reconnect.

1. http://www.reddit.com/r/SimCity/comments/1a9n5j/you_can_edit...

2. http://www.reddit.com/r/Games/comments/1a9t0e/simcity_modder...