[wtetzner]

> After all, I am already writing code in a rich programming language, why don't I just use it for my application logic in the first place?

I'd assume it's because that rich language isn't as well-suited to the problem domain as the DSL. I think one solution might be to come up with a more principled way of writing DSLs, that don't require you to revert to writing an interpreter or compiler "from scratch".