Absolutely not. It depends more on what you're doing, rather than number of people, anyways. One person uploading a video is going to use 99% of the available upload bandwidth.
That's a traffic shaping problem, not really on the person or service. Streaming would be a better example because that's immediate and you care about uploading in a timely fashion and best quality, but if you limit your upload bandwidth you can manage it better....
But then again we're talking about upload, in general, upload only matters in a few situations, latency will be more important, and download is always more noticeable than upload speeds.
Even doing making youtube videos the only reason you need instant fast video upload is if you're trying to push drama videos, and even then, I'm probably fine with them being slightly limited by that. But ultimately uploading videos is only slightly inconvenient for modern broadband, if it's that bad, look into how to limit how much bandwidth it takes up, there's good ways.
It doesn't matter what they are. That's how TCP is designed to ramp up until it fills the pipe. Upload a large continuous file and you will fill the upload until it's done.
Yes. The point is how long it cripples a network, due to the extremely poor upload rates allowed by service providers, is unacceptable. I'm not sure what's confusing here. It should be barely noticable by other users because it should be FAST.
That's due to the shit queuing most ISPs implement. You can limit your bandwidth below your actual limit on your router and do your own queueing that prioritizes TCP acknowledgements and you won't destroy your connection when you hit max upload.
Exactly. I had to implement QOS on my network otherwise my backups would kill my Internet connection. Now at least I can leave everything at 100% upload rate and let the network devices handle my traffic.