Yeah, they're proof that this sort of thing can be valuable.
But they have a very different approach. Proprietary language, components, etc. I wouldn't want to be locked into their ecosystem. That's typical with game engines, but not with web and mobile applications these days. Even Microsoft has gone full open source. I wouldn't use LiveCode as the basis to build a company on.
I'm building the open version. Made for startup teams and indie hackers that want to make world class products on top of the open source tools they would probably use anyway.
Interestingly Livecode had a GPL version until a few months ago. But I can’t wait to see your project, which sounds right up my alley. You could build yours starting with JUCE which has done an immense amount of heavy lifting in the portability department. It is also GPL.
https://livecode.com/