If people downgrade from MySky to the Sky Sport now, Sky doesn't have the cost of the Decoder, they don't have to send installers out to people houses, people are responsible for their own gear not Sky, so the drop in price people are paying is not a complete loss in profit to Sky.
Without starter Sky charges $19 decoder rent only fee. Now it's just $6 more to go to startup, but use to be $31.
They'll have a surplus of decoders if people start returning them to start with, but those decoders wouldn't have lasted forever.
If the startup channels can't stand on there on two feet, is it fair that people that only want Sport pay for that, and vice a versa.