Anyone who signs upto those tariffs are seriously brain dead, especially as its not available in 98% of the country and any tarrif under 8Gb is pointless and you wouldn't need 4g in its current state anyway.
They are going to lose out on huge amounts of potential two year contracts and tie us in, before the others get to market.
Not everyone is free to migrate right now from other networks. They have been smart in realising they are in a unique position to make it cheap for current EE users to migrate to expensive 4G tariffs before the competition comes online.
I'm sure someone like EE hasn't made this decision without very good consumer modelling.
I reckon the iphone 5 market alone will make them a lot of money.