Did you even bother to read my post properly?
Each user will have a lower % time used than what they currently do which will reduce congestion over time.
Let's say you currently have 100 384k users on a given exchange, now each users downloads his 6 linux distros a week that he watches at let's say 600MB each, so that's a total of 3.6GB per week per user.
3.6GB at 384k will take roughly 25.6 hours to complete, for those 25.6 hours that users is using his shared portion of the capacity all the time.
Now give them all 1Mb lines, now the download will only take 9.3 hours, which means that each user is now spending 16.3 hours less downloading than what they previously were allow other users to use capacity they were previously using all of the time.
Now take this across the 100 users, so the 100 users would've been using capacity for 2560 (106.6 days) combined hours while now they will only be using 960 (40 days) combined hours which is a significant reduction.
Think of it this way, you're travelling along a road at 60KM/h, it will take you 6 hours to cover 360KM, now they increase the speed limit on the road to 120KM/h, it will only take you 3 hours to cover the same distance after which you get off the road and another user can take up your spot.
As Sting pointed out, the users are going to try and download the internet in the first few weeks but will soon realize it ain't that great and go back to normal usage patterns.
Think before you post.