To suck customer money as ARP in the name of price reduce old poor marketing strategy by airtel meanwhile their ARP customers are only 10% rest all are monthly payers for telling correctly ₹200 payers so only reduce the price in ARP
Giving discounts on semi annual or annual packs is done by all companies across various sectors. It is not sucking customer money but a justified way providing the customer benefits for making the payment together. Both company and customer derive advantage out of this, company gets bulk money which is not assured if a customer is on monthly plans as there can b time periods where customer does not recharge account... Company can invest this money or put it in saving account to earn interest and also it helps in keeping subscriber churn rate under control while customer gets their favorite channels at lower cost bcoz of discount offered.
Above plans r special plans hence even in the monthly plans customer is getting channels at much lower price and if one opts for semi annual or annual variant then some more money can b saved