These missiles will be moving at mach 5... this is not something you can dodge like they do in the movies and even if you could at the last seconds of interception the proximity fuse means it can miss the target by several metres and still achieve a kill.
Ramjet/scramjet makes it more dangerous at long range.
Is there any combat experience/data that actually shows that to be the case?
On paper, I agree that with a working engine the missile will be able to manouver much better than a rocket powered missile whose fuel burnt out and is not coasting... but having an engine running does not allow a higher g turn, it just means when you pull a high g turn you lose less speed because you are still being pushed forward by the engine... so a high g turn at the last second of the intercept means both would likely miss... the question is, will that powered missile have the energy to do a full 180 degree turn and come around again and have another go at the target... but at the air speed these missiles are moving at a 180 degree turn might take an enormous volume of airspace... the SR-71 spy plane when flying at mach 3.2 couldn't turn 180 degrees and stay inside the airspace of the state of California... by the time it had turned around and headed back will the target still be there... and if it has dodged the missile once... is it not possible that it might dodge it again?
And russia has a long experience of making them. It is weired they never finished the r-77 ramjet version.
Not weird at all... perfectly logical.
If they are making catapults for aircraft carriers right now they will make EMALS cats because any catapult system will be expensive and time consuming to develop so you might as well spend that money developing the new system rather than an old one.
With missiles it is the same... across the board the Russians have been consistent in their weapons development programme... first upgrade existing tech as far as you can, and then introduce new generation tech... potentially upgrading the old with basic new tech for the new, but the new tech is a generational improvement compared with the upgraded old stuff which is an improvement but not a generational one.
Examples are the T-90 and the Armata T-14... the upgrades to the T-90 improve the fleet performance fast and can be applied to older models like T-72 and T-80 upgrades, while the generational improvements go to the Armata, Kurganets, Boomerang, and Typhoon vehicle families for the future.
In aircraft there are the MiG-35 and Su-35 upgrades, and the Su-57 new generation.
In their air to air missiles they had two upgrades for the R-77 ARH missile... one was a ramjet powered model and one was an improved rocket motor model... and they have said that the rocket motor option was quicker and easier and achieved the required performance so they decided to close down the R-77 ramjet upgrade programme and just focus on the R-77 improved rocket motor programme because they could get it into service quicker and easier.
I would also suspect that time spent on the ramjet model would be largely wasted as as soon as it is ready it will be eclipsed by the replacement missile that will be adopted to replace the R-77 family that will likely be a scramjet powered missile of much better performance... likely with twice the flight speed of the ramjet or improved rocket model and therefore much better speed and range performance... and not hugely more complex in terms of development.... the new missile could start as a ramjet and be upgraded to a scramjet as the new motor technologies are improved and perfected...