As noted by Vladimir Popov, deputy editor-in-chief of Aviapanorama magazine, honored military pilot of Russia, since the 70-80s of the last century, fighters and attack aircraft with two engines have been produced in the USSR. This was due to the maintainability and reliability of such equipment. That is, according to the expert, even if the plane received some damage, it is still capable of reaching the airfield. And the pilot also turns out to be alive, while if the same situation occurred on a single-engine fighter, the pilot would have to eject.
However, according to the expert, the transition to a single-engine aircraft does not mean that the country does not care about pilots. On the contrary, thanks to a special technology to reduce the signature of the Su-75 (or Checkmate), it is practically invisible to enemy radars. Also, a single engine allows you to reduce the visibility of the aircraft in the infrared range.