The absolutely massive advantage of BitTorrent over older networks is that current downloaders (leechers) can share the parts they have already downloaded. So instead of just a few seeders getting hammered with traffic and hitting a bottleneck as on Limewire, etc., you can get just the parts you need from the critical seeders.

Trackers also make this easier by avoiding the slow search through nodes and broadcast issues that P2P gossip-style networks have.

That said you could totally imagine a client that lets you share .torrent files like Limewire, etc. with direct search, and even merging it with the concept of trackers - like how RAFT can maintain a list of active nodes - i.e. you could just track the peers per torrent, and then let the actual traffic take place via direct connections like BitTorrent does.

I highly recommend reading the libp2p docs - https://libp2p.io/

The various Wikipedia articles on Gnutella, BitTorrent etc. - https://en.wikipedia.org/wiki/Gnutella

And Tailscale's article on NAT traversal - https://tailscale.com/...

To appreciate some of the challenges and development over time.

I really wish someone would write a book like How Music Got Free, but about the technical history and challenges of piracy / file-sharing. From Modem BBSs to Usenet to Napster, Gnutella, BitTorrent, and Freenet, I2P, IPFS, etc.