Nirbhay was a tech demo sort of project, to establish the baseline technology for cruise missile program. This is something I noticed now, like with uttam radar, HSTDV , all these are sanctioned tech demo project where you establish a baseline working tech, validate every parameter, control logic etc. Basically application of a theory. Turning that application into a product is the next stage, like now uttam radar is being created separate for separate jets, or Nirbhay was the precursor, now multiple cruise missile program underway based on it. This is why DRDO do the tech transfer. A minimum number is sometimes made project specific, to show the sanctioned money had some end product, like limited series production to justify to cag report type committees. HSTDV similarly will be closed once tech is validated, then multiple programs will sprawl from it.