Why would you request a fastlane for Netflix? As you can just buffer the video. If it's not fast enough you need a better internet connection.
Current internet connections are fast enough, future ones may not be.
Video file size will continue to increase. Connection bandwidth will not increase if ISP's can earn money from not increasing it.
For fast paced multiplayer games you would request a fast lane, or any multiplayer game really.
For games you mostly need low latency, not necessarily high bandwidth (which is what the fast lanes are about).
But what connections can be fastlaned? If Netflix or Valve have to negotiate for users to have fastlanes, then it will still cause the same problems.
That basically sums up the entire problem. Content providers will all pay extra for the fast lanes, as a result all content providers' traffic will be equally fast.
Internet will be just as fast as it would be with true net neutrality but ISP are raking in a lot of money for doing effectively nothing.