What they are really trying to do is set up vertical monopolies. You would still be able to game on their network service, but only the games they sell would work properly unless you payed and extra fee to use the bandwidth you have already paid for. Essentially when you sign up with a provider you won't be signing up for Internet access, all you are really getting is access to their private network. This whole private network model flopped badly back in the 90's because it was useless. Nobody bothered with it until they set up free exchange of data between the private networks.
In fact this connection between the independent networks is what the word "Internet" actually means. Throttling the connections between the various network providers is by definition restricting the internet.