The man with the whistle isn't going anywhere, but It will happen to some degree sooner or later. A lot of sports either already integrating or expanding their use of ML/AI into their judging processes from Football (Soccer), Tennis, Golf, Gymnastics etc. There is no reason the TMO need be just a human scrubbing video feeds when their role is to support the referee.
There are already systems like Trackswift (
https://www.personar.ai/solutions/rugby) used in Rugby and you could see some of the post game footage analyst platforms like Framesports (
https://framesports.ai/) and RugbySmarts (
https://www.rugbysmarts.com/) style platforms etc. being able to operate realtime with live feeds.