The problem is that the size of the market for cricket in India is massive compared to the rest of the world so it doesn't matter what the figures outside of India are (and it's certainly broadcast in every test playing country although I've no idea of viewing figures)
That's true, but if it's being broadcast but not watched in the other test playing nations, then the only country that will be affected from a test point of view will be India. Regardless of the level of demand for it there, if that demand isn't there in other countries, the IPL won't pose a genuine threat to test cricket.
There's a very good reason why Sky don't want to broadcast it despite wanting to show everything else.