I don't think DBP is an industry-capable language, if we're honest.
Consider that the DBP dlls (i.e, the work-horses of the DBP language) were written in c++, then you should begin to realise that if you want a career in game development, you'll need to be a c++ kinda guy.
Darkbasic (pro) will help you learn 3d programming, and how to put a game together, but you'll need to combine that knowledge with some serious C++ knowhow.
---edit---
Just read HZence's reply - he makes a good point. There's no reason you couldn't start up a game company which uses DBP. It'd be a nice little earner I'm sure...
Can I ask you a Question?
What is it?
It's an interrogative form of sentence, used to test knowledge. But that's not important right now.