>how do Disney and other streaming providers benefit from blocking 4K streaming in browsers once the 4K version is readily available to torrent, often at higher Blu-ray bitrates? Is this part of some backroom deal with TV and streaming device vendors?

Im pretty sure torrenting/piracy is a VERY small subset of people. I think it's been growing again, but everyone still thinks I'm doing things 'old school' when I mention illegally downloading movies for my Plex server

Edit: Google Search Trends for "torrent" suggest it is NOT on it's way back