I agree that the best transition strategy would be for grid/network operators to acquire these people as reactors reach their end of life and are decommissioned.
Plus, the TSO/Dispatcher role is a lot less bureaucratic than being an RO/SRO. I think most current RO/SROs would enjoy the job immensely more. You still get to operate a pretty large, intricate, and intellectually interesting system but without all the fuss of dealing with the NRC.