The value of this largely depends on what you're optimizing for. If your constraint is you need a lot of cheap bandwidth but don't care that much about latency,

The value of this largely depends on what you're optimizing for. If your constraint is you need a lot of cheap bandwidth but don't care that much about latency, there are many places to find it (find a cheap host, set up Varnish, you're good to go). However, a lot of people use CDNs because they are fast. They want the latency to be ultra low and they want it to be reliable. This is where the author's solution falls short: CDNs can get premium quality bandwidth because they have more scale than their customers. Sure you can find servers from various hosts in lots of different data centers, but you might not get the latency or quality of bandwidth you were looking for. This can be critical for some applications like streaming or serving images. If your constraint is speed, you almost have to go with a CDN (even if you are huge). If it's volume, you are in a better position. If your volume is small, you might as well go with something off the shelf like Cloudfront or Cloudflare. If you are ultra huge like YouTube or Netflix, then you have to peer directly with ISPs.