[jmillikin]

Purely my opinion:

There was an era of stability in the Haskell project during which it was possible to write code for industrial purposes. A lot of people were attracted to the idea of a memory-safe language that compiled to native binaries, and there wasn't much competition in that area at the time.

Then the research-oriented nature of the language and community re-asserted itself with Haskell 2010, and there was a lot of churn in both the base libraries and Hackage. Around this time was when Swift, Go, and Rust had their first releases, all of which offered memory safety and varying levels of ML/Haskell inspiration. So Haskell was suddenly less appealing, and there were other options -- why file another perf-regression GHC ticket into the void when Go has an HTTP server built right into the stdlib?

[tome]

I don't think it's got anything to do with Haskell 2010. Haskell is far more widely used in industry today than in 2010 by at least an order of magnitude. Heck, Mercury alone has about 250 Haskell programmers I think. That's probably more industry Haskell programmers than there were at all in 2010.