Exactly; but I would rather say that you don't need CDN unless you have tens of thousands of requests per second and your user base is global; single powerful machine can easily handle thousands and tens of thousands of requests per second
That's 1 Mbps per user. If your web page can't render (ignoring image loading) within a couple seconds even on a connection that slow, you're doing something wrong. Maybe stop using 20 different trackers and shoving several megabytes of JavaScript to the user.