Earlier quoted context omitted.
It's just basic economics. India and China have a bigger leverage, it would be stupid of them to not use it. I mean, what's the alternative explanation of why India increased the Russian oil imports tenfold? It's not because of good will, it's because India can suddenly import Russian oil much cheaper than before. Why does Russia sell oil cheaper to India? Because it won't find another such big customer.
Basic economics say that Russia is a major commodity exporter and that as long as there is global demand for these commodities then Russia will have no problem selling them. It's like you don't understand how basic supply and demand works. India gets a great deal because it can buy oil from Russia at a slight discount and then resell it to Europe at a large markup. The loser here isn't Russia but Europe.
You're contradicting yourself. India is selling at a market rate, so if there's a profit to make, it's coming from the Russian side. Pick one - either India has a big markup or Russia sells with only small discount. Both can't be true.