This is very true, and it's absolutely something that we don't understand. But Carroll's point in this blog post is simply that we have no reason to think that

This is very true, and it's absolutely something that we don't understand. But Carroll's point in this blog post is simply that we have no reason to think that the ultimate answer to these questions will require some fundamental principle of physics that is not ultimately a consequence of quantum field theory (and specifically, the standard model) and general relativity as we understand them today.