I don't think this is true... My friend used popcorn time and I can tell you that it is not easier or more reliable. The movie comes in somewhat random chunks so most of the time you are stuck having to download a large portion of the movie before being able to view it. The content discovery is lacking too. You have to rely on people hosting old movies and most of the time only blockbusters or recent movies are available. If you do get lucky on more obscure films, downloading it becomes an issue because of lack of seeders, and seeders come and go.
It is close to Netflix quality, but still not quite, which moreso is evidence for my "will always be at least as costly" point. Pick a not-super-recent and average-popularity film, say V for Vendetta, and see how Netflix and Popcorn Time compare.
You can also think about the tech: one ensures it's hosting high quality content on reliable servers that have the highest possible connectivity to its users. The other relies on users' good-will and connectivity, and both of those come and go.
Because Level3's peering agreements with Verizon/Comcast are under negotiation and the 10 high bandwidth data center owners don't want to set a precedent of paying more for a pipe because the end users want it (and are paying both services already), so the streams get throttled. But with a decentralized world, maybe it's harder to track a bunch of small packets that never leave the Verizon/Comcast network.
Source: https://www.theverge.com/2014/7/21/5922793/verizon-level-3-n...
Is it more expensive, though? In a lot of cases it is certainly more expensive (bitcoin, Facebook, etc) but Netflix should be a counter example. In theory, a decentralized Netflix should be a lot cheaper because there are very little bandwidth costs. In practice, though, this is impossible because of all the DRM regulations. There is just no way one could design a decentralized network without getting into legal troubles. Furthermore, adoption would be another problem because a decentralized Netflix would mean I have to upload content and download it. In practice, this would put me a long time into jail if I did that in my country (sometimes even more then murderer and rapists).
We have only seen one such successful "decentralized" application so far: popcorn time. It proves that it can be more reliable and easier to use but in reality the legal implications are just too impractical.
Furthermore, decentralizing other video platforms such as YouTube could be a lot harder. Netflix has a small amount of viewing content but a huge amount of viewers. YouTube has a lot of content and less viewers per minute of content then Netflix has. This means any user would have to store much more then they would on Netflix. There is just no way to save content for a long time. On YouTube I recently found a video I did when I was 13 about a tutorial for a video game. If I stored it on a hard drive, I would have lost it for sure (because I never really cared about it much) and there is no way it would have been stored for some many years by just 3000 viewers who have ever seen that. Just seeing this video after all those years is kind of amazing. I know that there is no guarantee that this video will stay on YouTube forever but the chances are a lot higher (and I don't see it disappearing as long as YouTube stays popular and their main business model is make small video makers big)