sky would love to be able to price discriminate as it costs them very little to serve one extra customer - they don't have to produce a new TV show for each customer, there is only a small cost off acquisition and set up. the product is easily served up to the extra customer for a fraction of the cost of production. also there is no danger of you reselling the product. its a perfect market to maximise volume on sensitivity to price. if they could manage it.
so if they could magically read your mind and say shoenstar would pay up to £60 pm then that is what they would offer to you
now the nice couple down the road are not price-sensitive, they will pay £100 pm
but they cannot advertise two prices. they can only advertise one so what they will do is bury offers in places that savvy shoppers will look for. and then advertise full price with an introductory offer elsewhere.
then at the end of the contract the price-insensitive people won't negotiate. and you will and so the retention team can make sure cost-aware customers pay less than people who are not price sensitive.
who is getting ripped off? well, it depends on your perspective.
if you are paying £100pm then you must value that service more than you value the £100. so you are getting a good deal. you could get better if you tried, but you are voluntarily exchanging money for a service that you value more than the price you are paying for it