Simple Reason
Still OTT has limited reach due to less internet penetration, even mobile internet speed unstable and now even rates going up. So having TV content available on OTT does not affect TV ratings in even minor way, just a too tiny loss. 2ndly 24 Hrs earlier release of TV content on OTT is for paid subscribers so whatever little loss happens it gets covered with this and ads
Lastly when stage comes that large number of people start watching content on OTT then most of content will go under paid subscription till that time enjoy free hindi or regional or hindi dubbed hollywood movies on platforms like Disney+ Hotstar. Netflix, Amazon Prime Video already has all content under pay wall as they have to earn only thru that but a freemium ad supported version will come very soon