Starlink cost is 499$ for equipment and 99$ per month? That is way too high for broadband prices in India. Fibre internet of 100 Mbps is about 18$. Mobile 4G is even cheaper.
How many people have access to this 100 Mbps fiber though? From what I'm seeing on Wikipedia, the internet penetration rate is around 50% of the population. Starlink isn't intended to replace existing reliable broadband solutions. It's meant to provide internet access to remote areas where running fiber to those areas is way more expensive. Fiber and cellular (usually needs fiber backhaul) would be prohibitively expensive to bring to many areas of the world and telecoms won't do it unless the government pays for it. But for $500 up front and $99 a month you can bring 150-300 Mbps to remote villages and schools. They don't need a dedicated connection per household, 300 Mbps is enough to split across potentially dozens of households or even a smalls school.
There are many cellular coverage maps out there that you can overlay with population graphs, but I can't link you to anything specific besides just a coverage map. But this isn't a problem unique to India. Many countries have holes in their coverage, including the US. There are many parts of the US where you'd be lucky to get 1 Mbps down on 3G. Or where your only broadband option is DSL at a few Mbps.