Russia is putting money, in the form of lots of new orders, into its military aircraft industries. The main reason for this is to keep this industry viable. But another reason is the continuing decline of the Russian commercial aviation. Unlike the Russian air force, which does not buy foreign aircraft, Russian airlines do. Even though Airbus and Boeing planes are more expensive, they are much cheaper to operate. The Western engines burn less fuel and last longer. The Russians have never been able to match the West when it comes to aircraft engine quality.
The commercial aviation business is very competitive. Without the more efficient Western airliners, Russian airlines could not survive. Over the last few years, as the price of fuel rose sharply, most of the Russian built airliners, with their inefficient Russian engines, simply became to expensive to operate. Last year, Russian air transport manufacturers received orders for only eight aircraft. The major manufacturers in the West received a hundred times more.
Russian military aircraft may be equally inferior to their Western counterparts. But, unlike commercial aircraft, Russian warplanes are not at "war." There are many foreign customers for cheaper, and less capable, Russian warplanes. And now that the Russian economy is on the rebound, the Russian Air Forces are buying again as well, and only buying Russian aircraft.