[znfi]

Firstly I think that Bittorrent-style techniques are or have been used in some places even though it may not have been advertised very clearly. For example until a few years ago Spotify used to use something like Bittorrent to reduce the load on their servers. It's just that they didn't really tell anyone who used their product about this, which I honestly felt was kinda bad style.

Similarly I heard that Skype used to do something similar, I'm not sure exactly how it worked and apparently it was a pain to maintain so I think it has been scraped as well by now. I think some software updaters do use Bittorrent still, though.

If I were to guess, the really big reason for the lack of interest from big corporations is that collecting as much data as possible for use in machine learning is very much in vogue, while at the same time bandwidth seems to be very much a no-issue. Thus there is not much to gain and possible something to lose from employing bittorrent.