Sounds like due to saturation or overkill of cricket than anything else. We used to have 3-4 bilateral (at most) series a year, only one world cup every 4 years. some tri or quadrangular series here and there. now we have another format, t20 world cups every two years and all these franchise leagues.
plus this is a dying format as well. Contrary to what most people say, ODIs are not what they used to be and are on their death bed. Now that I am thinking about it, I can think of a few more plausible reasons for the poor crowd turnout than "we got other sports" or "better things to do" because none of them seem to make sense to me.
What else is going on in India right now that the public would be more interested in?
There are lots of things. Like cable tv, OTT, internet , gaming , social media
In the 90s India was desperately poor. For most Indians entertainment meant cricket & Bollywood. One reason both were so big
But last few years with rising prosperity, Indians have far more options. Like K Pop, Afro beats, NetFlix, Amazon Prime, UCL, EPL, La Liga , NBA, Formula 1, Tennis, Super Bowl, Golf, Gaming, Instagram, Vblogs. Just look at record number of Indians who travelled to Qatar to watch Fifa World Cup. I myself was hardcore cricket fan in the 90s & 2000s but now I am more into football, badminton & wrestling
Also India started doing well in other sports. Today folks like Neeraj Chopra, PV Sindhu, Mary Kom are big superstars in India comparable to cricketers. So there is growing interest in other sports. IPL is not the only pro league in India. We have similar leagues for football, kabaddi, badminton, volleyball, handball, wresting among others. The football, kabaddi & badminton leagues are doing really well & growing fast in popularity
All this means cricket ( & Bollywood ) no longer has monopoly on people' attention. Of course they are still big but other fileds are slowly catching up