You know that you can't connect to normal bittorrent clients from webtorrent in browser right? Which means that you do not have almost any sources of seeders, which means that webrtc adoption dosen't matter.
"Which means that you do not have almost any sources of seeders"
All it takes for someone to seed a file is to open a web page. Think about it.
At any point if I wanted to promote a song via WebTorrent, I could build WebTorrent into an audio player and encourage my user base to click a checkbox and seed the track (toss in IndexedDB support for storing it offline and it's even better).
Complete serverless resharing with almost every benefit of BitTorrent to boot.
The only thing WebTorrent needs the existing BitTorrent install base for is the existing torrents, which don't matter as much as you might think they do (most torrents are pirated content anyways).
So yes, WebRTC adoption does matter.
You're missing the point.
Think of it this way.
Check out this video: https://fastcast.nz/videos/cityscape-chicago-ii.html
Once you're done viewing even a second of it, just know you've just adopted WebTorrent.
You don't even need to know WebTorrent exists or was used and BitTorrent wasn't needed in any way.
That's a pretty big hurdle considering most regular torrent users don't even realize WebTorrent exists, and these users contribute the vast majority of the content available on BitTorrent.
Of course in the ideal world where WebTorrent has significant market share, this wouldn't be nearly as much of a problem. But I agree with lossolo that without interop with libtorrent at the very least (if not uTorrent as well), that ideal world is probably never going to come into existence.
They don't need to. That's the point.
If I send a user to https://file.pizza/ to transfer a file to them. Not once to I have to mention that it uses WebTorrent. IMO that's the killer feature.
I already said "the forest" doesn't matter.
Seriously, if I were building something with WebTorrent. Let's say Netflix (Note: https://torrentfreak.com/webtorrent-brings-bittorrent-to-the...). And most of the existing BitTorrent seeds are pirated content.
Why would I care?
"there's no guarantee that any of them will ever reach critical mass in terms of adoption"
When you give away tool with a widespread guaranteed userbase like this, someone is bound to build something that people will use. Not to say WebTorrent will be this big, but that's how the internet came to be.
And this is a completely decentralized upload and download library for the web, someone's going to build something popular with it I'm sure and it's not even at version 1.0 yet.