Just to further this point: AFAIK, The BitTorrent protocol was not designed in order to stream content in any kind of order. I think the emerging P2P web technologies is good opportunity to iterate on BitTorrent and design a better-fit protocol.
Bittorrent the network, now, lives because peers have an incentive to behave correctly and spread the content on nodes as much as possible. It's a specific use of the protocol, but not the only one. The problem is that many people (even technical) conflate the protocol with how it's used the most: spread stuff illegally. In order to do this there is a need for peers fetching parts out-of-order. But if, say, Netflix were to distribute its content over Bittorrent, it would be perfectly fine to stream in-order, because the Netflix peers all have all the content so there is no need to spread the content here.
And there already is an enhanced protocol, in the IETF pipeline: PPSP [0]. It integrates a lot of good things that were incompatible with Bittorrent yet desirable. It's also called swift (before it was cool), and has 2 implementations [1] [2].
[0] https://datatracker.ietf.org/doc/draft-ietf-ppsp-peer-protoc...