Just some speculation, but one reason why C and friends took off better in enterprise domains is that they were on systems that people needed (C with Unix) or were more aggressively marketed. (Java) functional programming languages tended to not be as fast for single threaded programs compared to their imperative and object oriented counterparts.

Now that we have stopped seeing such large gains in single thread and performance, most of our scaling comes from being able to scale horizontally. Functional programming languages are making a resurgence: the rise of Rust, Elixir, Scala, etc. is in response to this.

I’m sure pg has plenty to say on the topic.