iPhones are ridiculously expensive in India because of the import taxes - a decent chunk of the population would be able to afford them if they were brought in line with the US prices.
Right now iphone 13 price on amazon is ₹73,990. US price before sales tax $799 which is ₹60,646. Add 18% GST which is charged even in product manufactured in India, you would get ₹71,562. So basically around 3% is charged as import fees.
iPhone 13 is listed as ₹69900.00 (920$) vs. $799 in the USA. The former includes taxes, so its only fair to add $80 to the latter (taxes in my state are 10%), so it is still around $40 difference, which isn't bad.
But it appears that the iPhone 13s sold in India today are already being produced in India. If that is the case, any secondary resalers on Amazon are going to take a loss if they imported the phones the hard way (though they could have just smuggled them in).
A correction - the price of Rs.69,900 is for the iPhone 13 mini. The iPhone 13 is listed at Rs.79,900 in the Indian Apple store (~$1,050 against $799 in the USA).
The base sales tax, which is GST in India, is also a lot higher (18%) than the average in the US (guessing it would be around 8%). A decent chunk of the population would be able to afford iPhones only if Apple reduces prices drastically and the GST rate goes to 12% or 5%. Neither of these are likely.