I think Evan's pointing at something, and everyone's looking at the finger. I don't think this is really about Elm at all, but the preparation for Acadia.

In his talk, Economics of Programming Languages https://www.youtube.com/watch?v=XZ3w_jec1v8, he does reveal a peek at what he's been working on for the past seven years: a query language with functional ideas applied to them.

He points at the boundaries in web apps that typically destroys type information: - language <-> storage - storage <-> wire

What if we could preserve the type information across these boundaries? What would that buy us? One answer he had was easier migrations. They'd just be a type diff, rather than hand-written SQL.

So I think the right question is, can we infer what Acadia is going to be like given the changes he's shipping with Elm? What does incremental compilation give query languages?