> True, but jQuery does a lot more than just id selection with $!
Yes. For a high degree of jquery-compatibility, you can use my library.
const $ = document.querySelectorAll.bind(document);
You could just extend the function to detect '.' vs '#', and do a class selection as well. And then add all of the selectors, subselectors, etc. (similar to, but far more powerful than css3's selectors.) and if you go far enough, you reinvented zepto (but still a long way from jQuery)
(actually, since $ is basically synonymous with jQuery, it'd probably be better to choose a different function name. too bad you can't define it as #(id).)