This could probably be contracted out to some small company for $1 million/yr, but it would violate some bureaucratic rules within NASA that demand they waste money internally. On the other hand, NASA probably can't oversee a contract for less than $4 million/yr lol.

I don't know though. It seems like if keeping Voyagers alive was big scientific bargain, someone in the scientific community could fund raise the $4 million. I think I've read about some new developments in remote sensing what Voyagers are currently reporting on (interstellar shock encounter). If that is the case, it may be valid to cut them off. I'm not sure either way.