Using the iterator's .next() method in a loop - or the built-in expression for doing so - avoids maintaining an integer counter and indexing. It is simply not semantically the same thing, and you cannot approximate what iterators get you with your counting loop in safe Rust code. The difference in semantics is why one enables you to avoid overflow checks and the other does not, given the semantics of Rust which don't allow skipping those overflow checks in safe code.

At a "base level", every language is exactly equivalent - they are all approximations of a turing machine - so I really don't get that argument unless you are trying to argue that every language is really just C in disguise.