Actually speaking-this is one of many contradictory reports on this deal.There's not been much solid stuff on this in the Indian papers or any reaction from the Indian government.So what I think(& a lot of experts r saying) is that this is essentially a deal to supply spare parts(Engines,chassis etc) to Pakistan's fleet of 320 T-80UD(predecessor of sorts to the T-90) tanks,which it acquired from Ukraine about 7 years ago.
The T-80 being a Soviet system in every sense,was shared by Russia&Ukraine.The Russians refused to sell engines,optronic sights etc to Pakis-leading to deal to getting bogged down.Moreover Pakistan has an "indegnious" tank programme going on known as the AL-KHALID, which seems to be a straight rip-off of some Chinese tank.
Pakistan, as most of you know is rather tight on funds(has to beg to Washington or to its Arab bros)-so buying a 3rd tank variant of pretty much equal standard makes no sense whatso ever.
India &Russia have a variety of joint-programmes going on-a supersonic cruise missile,5th generation fighter(supposedly to be a competitor to the JSF),a medium transport aircraft&numerous naval&aerial systems .So the Russians would have to be out of their minds to sell tanks&that too 300 of them to the Pakis.
So in short-this is nothing but some wierd spin .
What you say makes sense. Like politics, armament traders make strange bedfellows.
For example: It sells the SU-30 to China and India (both nations are not exactly bossom buds), sells tanks to Pakistan and India (again, don't expect the two to be eating roti and sambusa together anytime soon), and Putin even offered to sell some KILO class D-E subs to Taiwan (via the US), when it sells the same KILO class subs to China! And in all those cases Russia gets serious money.
Now, at first glance it would seem Russia is nothing more than a P.I.M.P and nothing more. But then the geo-political facets come into play if someone looks at the intricacies involved.
For example the Sukhoi sales. The Chinese Su-30 version is the MKK (SU-30MKK). The Indian version is the SU-30MKI. Now, the Indian MKI is far superior to the Chinese MKK, primarily because Russia and India need (or will need) each other in the future as China's power becomes more concrete. Same thing with the tank situation. The sales to India are the best the Russians can do. In some aspects even better than the actual tanks used in the vast majority of the Russian armored forces. Why? Because Russia and India have a very strong agreement. The tanks sold to Pakistan may look similar to the Indian ones, but a fight between India and Pakistan would show some differences. And if we (the US) accepts Putin's offer (to sell KILOs to the US, which would then sell them to Taiwan) one aspect of that sale would be that the KILOs would be outfitted with advanced US sensor suites. The Chinese KILOs are very quiet, but the proposed Taiwanese KILOs (if the deal goes through) would also be very quiet, but with more advanced sensor and sonar suites.
Hence, Russia gets its coffers filled with cash and currency, and at the same time it still helps allies like India.
Now, it is a balancing act. Especially with China (since China's intellectual capital is increasing in leaps and bounds, and soon they will be able to upgrade the stuff Russia sells them and make it less 'monkey model.') But as long as it lasts it is a very interesting strategy, and one that should work until Russia starts to totally tap into revenues that should start coming from its oil and gas reserves (Russia has 350 billion barrels of the stuff ....50 billion more than Saudi Arabia).
Hence, there is the reason the Indians are not up in arms over the Paki sales.