Hi buddy! Answer is very simple bcoz star has not kept movies like Hum Saath Saath Hai for select airing, star/disney airs even such mass appealing films at various slots hence viewership gets distributed across it. Not like star/disney not getting ratings from old films but just that certain films get a spike in ratings for chs thus gap gets increased between them and competitors. Also if u notice u can see star is doing fairly on par with others in urban but gap is more in rural bcoz zee, sony air more dubbed south indian films which get ratings in rural belts while star has stronghold in bollywood, urban base.... This also commands diff ad rates thus not a major issue for either of broadcasters.... Star will still b getting good ad rates for bollywood films, hollywood films compared to what most dubbed south indian films manage to attract. Star Utsav Movies if lands on free dish, will surely get no. 2 slot
But yeah i do agree star needs to keep certain films for specific airings rather than showing them quite regularly.... They have lot of content but proper scheduling is required while sony requires lot more bollywood content. Zee again is doing too much repetition on z bollywood, and pictures and ze action is turning out useless