Hahahah seriously when IPL starts we tend to miss sooryawansham. Maybe that is what they have in stock to replay or maybe this illuminati, conspuracy lol: P
The reason behind these are!
A) they are cheaper. Every screening means royalty to the studio and the older the film the lesser royalty you have to pay.
B) South Indian dubbed films are way cheaper than the hindi ones and a great alternative to fill in the less exciting time slots like matinee shows on the weekdays. You would notice that all new films premier on the weekends.
C) Every channel has a library of content. New content is more exclusive and hence less played to maintain the novelty.