BitTorrent has proven itself quite robust & resilient since the DHT & magnet links were introduced. Projects like Tribler[1][2] have been the leading edge of technology, working to create better fairness, to beget p2p search technologies, to allow p2p live streaming, all based around BitTorrent fundamentals. There's still very little technology like it, that could conceivably replace it.
We have similar discussion only a few days ago [1], copying my answer here.
>Bandwidth is also getting cheaper. May be there is a floor somewhere, but we dont seems to have that in sight.
From the economic point, the fragmentation of streaming services will probably give it a resurgence.