At risk of disagreeing, I don't think it's greed that's making ISPs to prefer CG NAT and tricks like a single /64 for v6.
Home internet connections in India are insanely under priced wrt GDP per capita. Given our economic disparity, the ones who can afford and do subscribe to fixed broadband access constitute a miniscule percentage of the country's population. The only advantage that India offers to ISPs is cheaper labour for both rolling out the networks, as well as the tech talent needed to keep it running. But ISPs have a lot of hoops to jump through; bureaucratic red tapes and commissions/bribes - so much so that none of the gains realised from cheap labour matters anymore.
So when the equipment costs the same as any other country, transit rates are higher than most other countries (thanks to geography), and prices drastically under priced, the only way forward is to raise revenue through economies of scale - getting more people to adopt fixed broadband, while simultaneously cutting corners at every possible place. So we have CG NAT and tricks like single /64 v6 for customers, and an order or two higher contention rations than other developed countries. And if anyone wants more, they have to pay.