A good question that neither this crap article, nor the BBC article it links to on the specific BitTorrent claim, makes any attempt the answer. One would have to go to the single source of the claims - Sandvine - to figure it out. The closest the BBC article comes is this:

  The latest figures suggest that, as well as its share falling,
  there could be less overall BitTorrent traffic on the network.

Could be. How helpful!

Obviously an article proclaiming the "death of BitTorrent" in describing a protocol that continues to represent at least 7% of all traffic is pointless linkbait. If that's "dead", I wonder how we should characterize marketplaces (3.95%) and gaming (3.41%)? The web is clearly on its deathbed at a mere 10%, as well.

The BBC article suggests that BitTorrent's decline may be because "The use of 'dark nets' such as Tor and encrypted digital lockers is growing in popularity." I think that pretty much tells us all we need to know about how useful and accurate these articles are.

My question exactly. If something stays flat and what it's compared to grows 40% a year, it looks like it's collapsing.