Doesn't really matter though, still means (Slightly oversimplified) that a peer can connect to 10 hosts and not have to download at all from the origin server. Also this simply isn't true in a lot of European countries where upload and download speeds are equal, but that's a different thing.
On an 1:10 asymmetric connection, users would need to remain available for seeding 10 times longer than it takes to download (and presumably watch) the film to have a net positive impact on the system.
That's not exactly realistic, considering that a lot of traffic goes to mobile devices where this would outright kill battery life.
Can you explain what you mean by that last statement? It does not sound true to me. As far as I can tell (in my country) almost all consumer offers are asymmetric: ADSL, obviously, but also fiber. Symmetric offers are very much for professional access, and typically more expensive.
In Sweden, fiber (which is quite common) is pretty much always symmetric. 100/100 is common, many people have 1000/1000 and there is residential symmetric 10 Gb/s to be had. Asymmetric ADSL and Cable is definitely not uncommon though.
