Regarding Lisp's ordering, this has come up in the article "What if Lisp was invented by the Japanese?"[1]. Note also that in the comments to that article[2], I mentioned that "Japanese Lisp" is something I find easier to read and would prefer to write, even as a native English speaker.
If Lisp had been invented in Japan, maybe the main connective of an expression would have ended up as the last item visually: (1 1 +). Maybe.
However, it would still be the first element of the list in the abstract data structure: i.e. the equivalent of (car '(1 1 +)) -> +. (Or, rather, of course, ((1 1 +)' car) -> +. Let's use the fantasy read syntax.)
The main point is not that + is leftmost or rightmost, but that it's at a fixed position in the data structure, and that it is the first/most accessible position.
However, it would still be the first element of the list in the abstract data structure: i.e. the equivalent of (car '(1 1 +)) -> +. (Or, rather, of course, ((1 1 +)' car) -> +. Let's use the fantasy read syntax.)
The main point is not that + is leftmost or rightmost, but that it's at a fixed position in the data structure, and that it is the first/most accessible position.