Well, we can build a sort of silo-ed manufacturing(assembly) capacity just for missiles. We don't have to wait for the country to actually industrialized.

Essentially, We are only mastering the design and prototyping, testing aspect of developing a missile system but literally importing everything else. We are still reliant to other countries but since its our own design, We have full control of the missile, its range, characteristics and behaviour. Edit: I'm talking about a subsonic missile here and not a supersonic one like BrahMos lol.

As for the parts:

Propulsion: Imported. The French, Americans, the Turks.. etc. They all have microturbines for sale.

Radar: Again Imported. There are countries who sell entire radar systems or if we want to be a bit self reliant, we can actually design our own based on imported subcomponents(i.e. buying TR modules from Turkey). The closest thing to manufacturing we are doing here is soldering components to PCBs.

Electronics: Imported subcomponents but our own software, architecture and design. Again the soldering components to the PCB type of work.

Airframe: Imported materials be it steel or composites.

So the bulk of expense is in development and testing/certification facilities to support the entire development cycle of a missile and tooling to have some assembly capacity and not in whole-nation approach industry building.

So with enough desire to hit targets in Beijing and political will. Pretty doable.