There are a few obstacles that have been deliberately put in place since it's a protocol that allows for relatively cheap pirating, not to mention, p2p might by

There are a few obstacles that have been deliberately put in place since it's a protocol that allows for relatively cheap pirating, not to mention, p2p might bypass content controllers, as such we've all familiar with protect the kids angle that is used to try and stifle p2p protocols such as bit-torrent. But in the last few years I think it's the presence of cheap CDN data that has seen some web sites wind back sharing their files via torrent as an option, as well as the idea of being able to better track their data being a benefit to them, and of course moves to allow for the collection of more tracking data, some sites or content providers have found appealing too. With so many sites sharing data, though free, most just opt for seamless redirection, and quietly supply the data from the original cdn. I would guess this might be for legal issues, as such supplying the same via a torrent might land them in legal hot water. Then there's the issue of how a web site chooses to serve torrent data if no one else is seeding, such as using "get right" which not all torrent clients support. The final straw I think is the nag of incomplete data as a means to force sharing by some torrent servers. Good idea if the pool of users is plentiful, but if it's an old file that most people are done with it, it's a problem. A few years ago I recall a bunch of files I needed, I had to find another support area that did it the old fashioned way with http and ftp. I think what is required for to grow the adoption of torrent again, is a better implementation of serving files from the host site, such as a module that incorporates something like aria2c, that could serve torrents, but also access files from a hidden https / ftp area.