Comment by munificent

Your comment is very assertive, but also doesn't offer much in the way of science.

Being able to compile ML quickly in the 90s tells you little about being able to compile Roc or some other language today because the language design enforces hard constraints on the algorithms necessary to compile it and the hardware today is much more complex. It's not hard to write a fast Pascal compiler that targets a 1980s chip with shallow pipelines. But that's not the problem being solved here.

I don't know much about Roc but it looks like it's got some amount of overloading and the linked article alludes to sophisticated algorithms to avoid heap allocating closures. Those can enforce algorithmic complexity in the compiler that is essential and can't be eliminated.

Once you're at the limits of algorithmic optimization, all that's left is reducing constant factors. I've written code in many languages in different performance regimes over the years and it's certainly the case that higher level languages, especially managed memory ones, put a hard floor in terms of how low you can go when optimizing to improve those constant factors.

I have seen in real-world code where explicit control over memory layout improved performance by more than an order of magnitude. I have friends in the game industry where much of their career is this kind of work. Those people would love to live in the luxurious world you describe where all they need to do is find a sufficiently clever algorithm and all of their performance problems will disappear.