Those were all just pilots which were made and then aired for the dual purpose of filling airtime and testing viewer interests. That's the standard life cycle for a television show (most of which don't get picked up, but some of which get lucky).
This is the result of a far cruder and more unusual form of idea pitch. And though the end goal of gauging its viability as a full series might be a common factor, there is a great deal more logistical problems going from concept to 15 second animation to full-length cartoon than there is going from a full-length cartoon made by a minimal but still complete creative team to a proper network setup.
Clearly Cartoon Network is trying to set up a Mexican animation studio and animating this contest idea winner thing serves the dual purpose of testing the studio setup and getting administrative interest by demonstrating a product. Now it could be that this means, right place right time, someone up there likes the show and it's on a fast track to being the premier piece of this new venture they're undertaking. Or it could be something used up and spit out as quickly as it got this far (not unlike the fate of most pilots).