> We want to use the whole computer. Code runs on CPUs, and in 2023, even my phone has eight of the damn things. If I want to use more than 12% of the machine, I need several cores.

Isn't that already, in this strong generality, an almost always wrong assumption?

Sure, one can do massively parallel or embarrassingly parallel computation.

Sure, graphic cards are parallel computers.

Sure, OS kernels use multiple cores.

Sure, languages and concepts like Clojure exist and work - for a specific domain, like web services (and for that, Clojure works fascinatingly well).

But there are many, even conceptually simple algorithms which are not easy to parallelize. There is no efficient parallel Fast Fourier Transform I know of.