I do agree with you. When I signed up in early feb, the deal on the BT site for Infinity 1 was £39.99/12mth with a £125 reward card. I did this through quidco and it brought it down to £34.99/12mth. Infinity 2 at the time was £49.99 BT and £44.99 quidco.

The day after, BT dropped to £34.99/12mth with £150 reward card, or £29.99 through quidco with the reward card.
After that one ended...
BT dropped to £29.99/12mth with £125 reward card, quidco £28.49.

I've been connected less than a month and I am now paying less per month than I signed up for originally, for Infinity 2 rather than Infinity 1, albeit over 18 months rather than 12.

I doubt these prices are sustainable, especially once you include the reward card and the cashback. They can only do it because the vast majority of customers are paying full price because they are unaware/ignorant to the fact that cheaper prices are available if they look around or haggle.

Same goes for Sky/Virgin, electric and gas etc.

I highly doubt Sky would offer 50% off packages for 12 months and an account credit without much fuss, if everyone did it.

That said, I couldn't recommend BT to someone who I knew wouldn't be up for hoop jumping every year.

BT are not offering me anything lower than £41.49 per month for 18 months. Considering moving to Sky now as they have a £35 per month offer at the moment.

Im pretty sure i am now paying less for Infinity 2 and line rental than what i was paying for Infinity (no 1 or 2 back then) and line rental in 2011 when i joined BT, it's all a bit crackers.