We're yet to see if monoids, functors, and monads are worth it :)

For better I'd say you should look at things like virtual threads vs async/await or kotlins when vs switch expressions.

If you program modern Java or Kotlin map and flatMap are everywhere. I'd say the debate whether functors and monads are useful is over.

Java or Kotlin support functors or monads as design patterns, i.e. this is how a map/flatMap works with an Optional or a Stream.

The question is: if this support is enough or should the type system be enhanced so you can abstract over/compose a functor and/or a monad ?

The answer to this question is IMO still open.

No they are. Seriously, the mental effort I had to endure to hold all these wild APIs in my head! In hindsight it’s infuriating; the gatekeeping, the patronizing condescendence when I was struggling with what are mathematical trivialities.

Screw that... I should have been told sooner