The game has it's own development tools which are outdated and take a bit of learning to understand.
Surely, some developers with experience in Java and C# wouldn't want to jump down to GS2.
The profit is kinda there, but there's a lot of work to it.
It'd probably be a bit before anyone sees the gem in a small playerbase with player-made items running itself.
Of course, the downside is that the community is ran by itself, but I don't think an outside source would truly understand Graal.