The reference point for when we talk about low memory languages is not transistor but rather machine code. In this aspect we say that C is low level because one pointer dereference in C translates directly into memory load of machine code.
The fact that modern memory load operation involves cache, protection, memory mapping, etc.. is not a property of language, but rather of the environment (CPU + OS).
That's fair enough, but it doesn't seem to be the most useful that it can be then. Low level to me could mean that we control all the details. But modern processors have microcode between transistors and the x86 machine code. And we can't control all that memory stuff.
But those aren't abstractions that we can treat as black boxes, we need to know them and how to code taking them into account without actually having control inside the black box.
The fact that modern memory load operation involves cache, protection, memory mapping, etc.. is not a property of language, but rather of the environment (CPU + OS).