> If not, you can easily spin up 1000+ nodes and connect to your torrent. Tada fake popularity. If bandwidth is known, then you simply raise your costs a bit by running fake clients.

Sure, but like the other commenter said, this has been possible for years, and yet public trackers aren't swamped with fake torrents. I think in all my years of using BitTorrent I've only ever found a single fake torrent, where the content was inside an encrypted RAR with no key (obviously there was no way to know it was encrypted ahead of time).