bittorent has been around for decades and nobody used it. They emailed files to themselves instead, or used dropbox. This all happened before the ipv4 shortage and people getting moved to CGNAT.
no reason this has to be centralised.
in fact, Jitsi uses p2p with WebRTC until a third person joins the call: then migrates the call to be relayed.
A really nice latency win.
ISPs had/have whole groups trying to stomp it out.
And it was a nightmare due to NAT even then.
It just got worse with CGNAT.
Even Linux distros push you so direct downloads now rather than pointing to trackers.
BitTorrent only has healthy usage for content that’s untenable to host legitimately.
Also, hey now - I have a lot of (actual) Linux disk images, and it works well for that!