The problem is that it is just going to be the starting point. Test the waters with a few bucks, see how many people stick around, how many leave. Next slide in another buck or two, claim House of Cards as the reason you should pay more. Soon, its just going to be as bad as getting cable but without all of the channels that have 20 different pawn shop shows, history shows about people running around naked and or in a swamp chasing gators.
If Netflix continues to grow then cable companies are going to start reducing speeds, as someone mentioned a company already has. You can say "screw cable!" but most people are going to be using cable based internet to watch netflix. Its not as though you can select which cable company you can get internet access from, they have a legalized monopoly, so you have no choice but to pay them or go with something slower. Costs are just going to start stacking up.