I think the point is that a monad is a useful concept _purely_ because of what it _allows_ you to do, and _not_ because of anything syntactical. Those rules that you're obviating there, the commutative squares, are precisely what then lets us have powerful intuitions about these objects. The type signatures matter a lot less. If, for example, you don't have functoriality (which is false for `std::vector`, for instance, since `std::vector<bool>` is special-cased) you lose the ability to reason powerfully about abstract algorithms.
Thus, explaining the syntax and where the type variables go is explaining the least relevant thing about monads to their power and importance. It's certainly easy to showcase both the syntax and the list and maybe monads, that's part of the "monad tutorial fallacy". Gaining intuition for how to think about monads _in general_ is a lot harder and requires practice. Like, yes, list and maybe are "containers", but is `(->) t` a container? Is `IO`? How do these compose, if at all? What is this about "effect" semantics, "I thought monads were just burritos/containers"? etc. These are the hard, both conceptually and pedagogically, questions. Yes you need to know the syntax to use it in any given programming language, but knowing what scabbard your knife fits in doesn't give you the skills of how to use knife :)
Thus, explaining the syntax and where the type variables go is explaining the least relevant thing about monads to their power and importance. It's certainly easy to showcase both the syntax and the list and maybe monads, that's part of the "monad tutorial fallacy". Gaining intuition for how to think about monads _in general_ is a lot harder and requires practice. Like, yes, list and maybe are "containers", but is `(->) t` a container? Is `IO`? How do these compose, if at all? What is this about "effect" semantics, "I thought monads were just burritos/containers"? etc. These are the hard, both conceptually and pedagogically, questions. Yes you need to know the syntax to use it in any given programming language, but knowing what scabbard your knife fits in doesn't give you the skills of how to use knife :)