LiveCode has its place. It is fast and convenient to develop in. The primary issue is its distance to native APIs and raw speed for numerically intensive stuff. If the language doesn't support it, it is a bother to get there. Fortunately, it is rarely a problem.
On to the real question, can this be a successful? Yes, as others have pointed out, it has worked before in similar cases. In the dual license situation, you get the tool for free if you want to give your work away. If you don't, you pay to earn your income. Should it be successful? Yes - it is a very approachable language which is a benefit for those learning to program (the syntax stays out of the way) and, for the same reason, a fast, efficient, and comfortable language to develop apps in if you don't need raw speed.