I read an interview with an NRO scientist, who described his group as following carefully the progress of the Hubble team who were independently solving many of the same problems their teams had solved earlier. From a national security perspective, they had to sit on their hands and not offer any help, but from an engineering perspective, they valued having another team do it to see if they would validate their design by coming up with similar solutions.
Unless they also donated launch costs, and $90 million per year to run it[1], it's no surprise that they're not actually using it. It's small compared to the overall budget, but not free.
Those were mirror and optics/satellite body assemblies, not two fully completed unused spy satellites. The electronics, power systems and communications systems were entirely absent.
https://www.space.com/16000-spy-satellites-space-telescopes-...