Is there any reason why we can't completely make ramjet engines for

in house? If I am right, Akash (SAM) missiles were ramjet powered until recently when they were abandoned for dual pulse rocket motor. This reduced the weight of Akash missile and doubled the range of missile. I am starting to think they mainly did it for reducing the cost.
Now if we were able to make ramjet for Akash missiles, I am pretty sure we can churn them out in good quantity for

too. There are lot of sources saying we only have 2,000

missiles in our arsenal. True number obviously hidden. I say why not have a stock of 10,000 of them? Taking into consideration the time taken to assemble the missile, why not stock up on parts which can be put together quickly in war mode? Given the precision and effectiveness of this missile if we use this missile properly we can take out vital assets of our enemies quickly. I only hope we can increase the area impact of this missile with some high explosive warhead for more destruction.
Having more numbers would give us the freedom to target more assets of our enemies. Taking out supply lines of Chinese is vital to cripple them if we go up against them. We can drive the cost down if we fully indigenize the missile instead of importing ramjet engine from Russia. Maybe someone throw light on why we still import ramjet engine from Russia? Did we not make ramjet engines for Akash before?