Author here. Unfortunately, I think worded that a bit confusingly in the article. I'm used to working with runtimes that run TS natively and didn't have to care about .d.ts files myself for a long time. From that perspective creating them by running the tsc compiler feels like a manual step for me.
There are cases where folks write them by hand, but that's not what I had in mind when writing the article. I've rephrased that part a bit to hopefully make it less confusing.
The fact that there are developers out there that are willing to accept hour long compile times from the typescript compiler is disgusting. I’ve seen slow recursive types here and there, but you can analyze your slow types using tsc and fix them yourself.
I hope that slow typescript compiling is a niche issue for massively large/complex codebases and not a common problem.
There are cases where folks write them by hand, but that's not what I had in mind when writing the article. I've rephrased that part a bit to hopefully make it less confusing.