In 2018, there was a report published by Sandvine saying that BitTorrent traffic...

In 2018, there was a report published by Sandvine saying that BitTorrent traffic had increased on their network for the first time in years (Engadget link: https://www.engadget.com/2018/10/03/streaming-exclusives-may...)

It seems perfectly rational to me. Streaming platforms' competitive advantage vs piracy is convenience (being legal and easier to use). As their convenience declines, users who are not averse to piracy will naturally gravitate back towards it.