[i_don_t_know]

The hard part is finding the right abstractions on which to build your large-scale system. When you have those abstractions, you can build a DSL to help you implement your system. Or you can build an API for an existing language. They are two sides of the same coin and I can see arguments for / against either approach.

I think where your criticism is really valid is that they are building tools that they think will help them address the real problem. But it's not clear that they have a real problem yet and that they fully understand it. If they do and Eta is their "DSL" to solve it, then that's great.

I have way too often fallen into the trap of finding (or dreaming about) the right language / IDE / etc. to solve my problem instead of actually working on the problem and gaining a better understanding of it. It's so easy to spend all your time on technical details because it's fun when you really should be worrying about the stuff that pays the bills.