India has bought Russian arms for a very long time, (approximately 50 years) and while they are buying enormous amounts of arms from France, Israel, and the US Russia has also been the recipient of massive deals.
Russian arms and equipment have a reputation for being sturdy, easy to use, reliable under combat conditions, and reasonably priced. The Russians are highly advanced but their design strategy seems to be to produce ‘good enough’ weapons and not go for all the bells and whistles that could be installed.
India is a different category in terms of being a buyer and user of Russian arms. India’s technical and scientific abilities and the availability of well trained forces meant that India integrated and used their Russian weapons to its full potential. Many buyers of Russian arms do not have this capability. They purchase the arms for show, to look good in parades, and to signal their neighbors, but precious little effort is spent on actually training for battle with the weapon systems! The results are predictable as multiple states armed with top line Russian weapons are badly defeated in conflicts.
India’s record in 4 wars with Pakistan and 2 with China, interventions in the Maldives, Bhutan, and Sri Lanka, UN operations, and decades of fighting insurgencies in Kashmir and on the Myanmar and Bangladeshi borders are far different, and point to a well trained force effectively using its weapon systems.
Where Russia falls short, and thus loses some sales opportunities, is in aftermarket support. Russian arms manufacturers are notorious for abysmal support on spare parts, repairs, technical problems, and problem solving, and are also known to price gouge customers on spares. This loses them some goodwill and works against them for future sales.
India avoided a lot of these problems as they often solved the problems on their own, manufactured their own spare parts, and actually license built many of the weapon systems they operate, such as the T-72 and T-90 tanks, MiG series of fighters, 23mm autocannon and ammunition, 30mm cannon, BMP armored personnel carriers, Konkurs ATGM’s, 12.7mm HMG’s, and the like. This allowed India to continue buying arms from Russia, knowing they could safely ignore many of the poor support problems while still benefiting from Russian TOT and favorable deals.
Russia is aware that it might lose India as a dedicated customer and is making a valiant effort to develop JV’s with India to manufacture spares and carry out all repair and maintainence in India, solving a great many complaints at once.