It is not the first time that a mid-air collision has resulted in the complete destruction of 1 jet while the other is somewhat less damaged.
Remembering the MiG-29's mid air collision at RIAT 1993
In this pic one can see the catastrophic damage one MiG-29 took, but miraculously both pilots survived!
F-18 mid air collision result in this..but both aircraft were recovered since luckily neither sustained damage to the wings or the fuselage where the engine was housed.
In 1983, an Israeli F-15 landed with one entire wing missing after a mid-air collision with an A-4 Skyhawk.
The pilot actually stated that had he been able to SEE that the wing was almost completely gone, they would've ejected because no pilot would've wanted to stay on in the fighter with one wing completely gone. Only because fuel and air flow over it were obscuring their view, did the pilots try to land instead of ejecting. And it was supremely risky attempting such a thing.
1983 Negev mid air collision
What we don't know in this case is what were the kinds of warning or hazard lights that came on in the Su-30MKI cockpit after the crash. The pilots did the right thing in my opinion. Their lives are worth much more than the aircraft, which can be replaced. They can and will go on to fly other fighters. But the loss of the TACDE QFI Wing Cmdr Hanumanth Rao Sarathi is massive, given how good of an aviator he was and how highly qualified.