SC is not an online game, and comparing it to MMOs makes no sense at all. Sooner or later they will turn off the servers and make an offline patch. This game doesn't need online to be alive, it's actually one of the reasons why it's not bigger than it could.
i totally agree, an MMO is comprised of countless number of people playing the same game at the same time together, while SC2013 has online play its not an MMO by no means, MMO = Massively Multiplayer Online, while SC2013 is more like an LMO Limited Multiplayer Online since you are limited to how ever many cities are in a region, not to mention you are even limited more, because of the big maps have multiple great works that only the surrounding cities can assist in and are not linked to other great works and those surrounding cities.
SC2013's online is ultimately meant for storage and to make it piracy proof(ish) with a benefit of not having to create every city in the region