You will see it explode indeed (where "it" means "the browser" and "explode" means "tab gets throttled and/or crashes"). I understand the motivations for everything-in-a-browser, but this approach has major externalities - e.g. the client's power, both as in CPU and as in battery.

Something like a torrent network is a bunch of IO with some processing which fits perfectly with javascript. WebAssembly might be able to get around some of the performance issues in specific areas (like some of the more complicated hashing stuff) if there are some, but it's more than possible to write performant code in javsacript.

It might be possible, but I have yet to see it. So far, the performance increase has been thanks to the engine executing such code, despite the opposite effort ;) of the JS code.

sadly I believe that relies on special software bridges or gateways to talk to "true bittorrent networks".

Vuze already has a supporting plugin, and there's been talk for Transmission to include it. I'm not entirely sure, but I think that if 1 person has a compatible client it acts as a bridge connecting the two types of swarms via DHT!

Yes please, someone do this