Total bandwidth reduces because the files get cached at the edge. E.g. if I'm watching a Netflix movie from the UK that is originally hosted in the US, the stre

Total bandwidth reduces because the files get cached at the edge. E.g. if I'm watching a Netflix movie from the UK that is originally hosted in the US, the stream has to move to the UK, where it can then be cached, then it is also sent to me. For the first stream there is no bandwidth savings. Any additional person that watches the same only needs to get the file from the cached location, thus saving bandwidth between Netflix's hosting location, and UK. In contrast with p2p, bandwidth may or may not be saved for the ISP. If my peers are close to me, sure, but if all my peers are US based, then there is no bandwidth savings. Furthermore, when I stop stream the video, and I don't have parts any more, and another in my area is still watching, they now have to connect to US peers and/or origin server. This is obviously oversimplified. In reality, the best solution likely includes a CDN combined with P2P, which would maximise bandwidth savings for hosters and maximise performance.