The reliability in question is not so as its already passed its reliability tests on IL-76, What kaveri will be getting by fitting into MIG-29 is its compatibility ..
MIG-21 which is being suggested only because its going to serve till 2021 with a unreliable that cost so many lives, Kaveri suits the need, Besides if its a success then it also have a good export potential ..
The department can churn out Kaveri if their is a huge order, The deal with the Navy has this issue ..
kunal,
1) Mig 21 with Kaveri export potential - Do you think there are countries which would still like to buy Mig - 21 when we have grippen,KA-50 and even tejas?
2) when Kaveri was tested in IL-76 in 2012,five major issues were reported.Some of them were serious in nature like blade throw.There has subsequent reports that DRDO has ironed out all those issue.But to say engine is reliable we need a test bed and record atleast 1000 hours of flight. This is not yet done.Once it is done and we have no issues,we can talk about engine reliablity.
3)I do understand your concerns on Pilots life in Mig - 21. But even if we take the work of fitting kaveri into Mig 21 now,it will be almost 5 years from now,when Mig 21 with kaveri will be flight testified. Instead it would be beneficial to ramp up Tejas production and replace Mig 21.
4) Last but important points,engine prototypes are fine,but large scale manufacturing of kaveri needs to be done and it will take atleast 3-4 years to mass produce if we start now.
So looking at all these issue,i feel kaveri program should be fasttraked for AMCA program and tejas production to be ramped for Mig 21 replacement.