I thought I heard that there was some feuding going on between SDC and Branson... just rumors mostly, but it's well known that SDC has always thrown their weight around in Branson and has run off many developments that they have thought would be detrimental to SDC or their other businesses. In the last decade, Branson has been slowly rebuilding itself to be more than just the home of SDC and a few ancient country stars and SDC's influence has dimmed a bit.
I mean, they are still the main game in town, but with Branson Landing and a slew of new attractions on the strip it's not JUST about them anymore. Supposedly they griped heavily about the aquarium being built because they wanted to build their own aquarium in Branson "some day".
Or maybe they just thought that Ozark Mountains is better branding than Branson, which has a reputation for being a tourist trap.