Think I can list a few reasons.

[] Movie piracy: continuing through telegram groups

[] WhatsApp - people share videos on whatsapp a lot these days..

[] YouTube - Here I don't think ppl are much into paying for Netflix / Amazon, but YouTube is used a lot.

[] Others: services like hotstar, voot ( movie / TV live streaming ), audio streaming services. Most of these are ad supported. And of course, seems quite a lot at adult content..

This is what I observed in surroundings. Indian people don't care much about ads and that also has been a monetization strategy for jio. I personally don't use any of their apps but many do. Also their cheap feature phones embed advertising.