If PP is considering fee increases it is no doubt thanks to the many claims by people who keep getting scammed.  Refunds for INR have to come from somewhere.

They typically come from the seller's funds, or not at all - INR claims rarely cost PayPal anything, since they make it quite clear the buyer is not entitled to a refund if the seller proves postage. Ergo in those circumstances, seller would keep the money, and PayPal the fees.

Providing seller protection for credit card chargebacks would probably cost them way more than INR's, because if the chargeback is successful, PayPal foots the bill.