Functional programming is great. What’s not great is loading the entire closure VM environment into my browser - resulting in the software running (in this case) 50x slower. FP is no excuse for making my computer crawl to a halt.
And there’s no essential reason FP needs to be slow. For example, look at how well llvm optimizes map/filter/fold in rust. In many cases they’re faster than their imperative counterparts! There are other ways to benefit from immutability that don’t involve burying a garbage collector in useless work. For example, React is a lovely example of immutable ideas, and a fast runtime.
I spent a few thousand dollars on a new Mac laptop recently. I wonder what percentage of my clock cycles are going to be wasted due to bad abstractions and inefficient code? Probably most of them. I wish I could take the money I spent on the machine and instead pay people to improve their software. I don’t have billions of cycles per second of actual work to do.